Hong Kong Polytechnic University

About: Hong Kong Polytechnic University is a education organization based out in Hong Kong, China. It is known for research contribution in the topics: Computer science & Tourism. The organization has 29633 authors who have published 72136 publications receiving 1956312 citations. The organization is also known as: HKPU & PolyU.

Characterization of airborne carbonate over a site near Asian dust source regions during spring 2002 and its climatic and environmental significance

Abstract: [1] During spring 2002, three dust storm events were monitored by filter sampling in Xi'an near an Asian dust source region of northwest China. The carbonate (CO32−) fraction was determined by sample acidification and thermal evolution. The CO32− accounted for 8.0 ± 0.8% of particles with aerodynamic diameter ≤2.5 μm (PM2.5) during dust storms and 4.7 ± 3.0% of PM2.5 between storms. The ratios of calcium to carbonate carbon were consistent with those of calcite (CaCO3). The δ13C and δ18O abundances in dust storm samples were −2.7 ± 0.7‰ and −5.8 ± 1.5‰, which differed from −8.3 ± 1.9‰ for δ13C and −10.8 ± 2.0‰ for δ18O during normal conditions. The δ13C is positively correlated with δ18O values (r = 0.78). This first measurement of isotopic abundance in Asian dust indicates the potential to quantify its contribution at distant locations using receptor models. By increasing the alkalinity of ocean water in the Pacific Ocean and buffering the atmospheric acidity of east Asia, the large amounts of airborne CO32− (as high as 44.8 Tg yr−1) entrained by Asian dust may provide an important atmospheric alkaline carbon reservoir for large-scale climatic and environmental changes.

Stabilization of G-quadruplex DNA and down-regulation of oncogene c-myc by quindoline derivatives

Abstract: Stabilization of G-quadruplex structures in the promoter region of certain oncogenes is an emerging field in anticancer drug design. Human c-myc gene is one of these oncogenes, and G-quadruplexes have been proven to be the transcriptional controller of this gene. In the present study, the interaction of quindoline derivatives with G-quadruplexes in c-myc was investigated. The experimental results indicated that these derivatives have the ability to induce/stabilize the G-quadruplexes in c-myc, which lead to down-regulation of the c-myc in the Hep G2 cell line. It was found that derivatives with terminal amino groups in their side chains would selectively bind to the isomers with the double nucleotide loops in the absence of K+. Molecular modeling studies revealed the binding mode between the derivatives and the G-quadruplexes is end-stacking at the 3‘-position, and the positively charged side chain on the quindoline derivatives may contribute to the selectivity to certain loop isomers of topological quadr...

Investor Protection and Firm Liquidity

Abstract: The purpose of this study is to investigate the relation between investor protection and firm liquidity. We posit that less protective environments lead to wider bid-ask spreads and thinner depths because they fail to minimize information asymmetries. The Hong Kong equity market provides a unique opportunity to compare liquidity costs across distinct investor protection environments, but still within a common trading mechanism and currency. Our empirical findings verify that firm liquidity is significantly affected by investor protection. Regression and matched-sample results show that Hong Kong-based equities exhibit narrower spreads and thicker depths than their China-based counterparts. THE PURPOSE of this study is to investigate the relation between economy-level investor protection and firm-level liquidity. We posit an inverse relation between the quality of investor protection and the cost of liquidity. A good investor protection environment minimizes information asymmetries and reduces the probability of trading against informed traders. In such an environment, liquidity providers incur relatively low costs and therefore offer narrow bid-ask spreads and thick depths. This is significant because lower liquidity costs have been shown to reduce the firm's cost of capital and increase its market value.l To date, the liquidity hypothesis has been difficult to test empirically because firms operating in distinct investor protection environments also trade on different exchanges, thus complicating the task of isolating investor protection effects from microstructure effects. We overcome this obstacle by holding constant the market structure and allowing investor protection levels to vary. The Hong Kong equity market lists firms from very distinct investor protection environments, but traded in the same market structure. Using the unique features of the Hong Kong market, we test and confirm the hypothesized relation between investor protection and firm liquidity. Recent research demonstrates the importance of an economy's legal system on the quality of its investor protection. A market-oriented legal system reduces in

Helpful Reviewers in TripAdvisor, an Online Travel Community

Abstract: Online communities need a critical mass for communication, information, and entertainment and should provide useful information for their members in order to obtain this critical mass. The abundance of online travel reviews increases cognitive costs of travelers, and travelers use extrinsic cues to judge the quality of online reviews to eliminate costs associated with the information process. Of various cues used in online environments, this study examined an online reputation system in TripAdvisor.com and profiled the reviewers who post helpful reviews in the online travel community. The key findings include that helpful reviewers are those who travel more, actively post reviews, belong to any age and gender groups, and give lower hotel ratings. This study adds to research of online travel reviewers by characterizing helpful information creators among online content creators.