197 research outputs found

    Managerial shareholding policies and retention of vested equity incentives

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    Previous studies show that corporate executives tend to liquidate equity incentives when equity-based compensation vests. This undermines long-term incentives and destroys shareholders value. It is suggested that the unwinding incentives can be limited when the firm adopts a minimum executive shareholding policy. We provide the first evidence of the effectiveness of such policies. Using data for UK FTSE 350 companies, we find that executives whose shareholding is below the policy minimum retain more newly vested equity, and the incentives to retain shares decreases when executive shareholdings are above the policy minimum. We also find higher firm valuations when executive share ownership increases relative to the minimum holdings required. Our results have important implications for the debate on executive remuneration regulations

    An Empirical Study of Customer Satisfaction and Loyalty on Health Websites

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    Numerous health websites are developing rapidly in China and the competition is fierce between these websites. In order to win the competition, the websites operators need to satisfy their customers to attain more market shares. But few attention has been paid to factors affecting customer satisfaction and loyalty on these websites. As a result, the paper aims to empirically explore the factors affecting customer satisfaction and loyalty on health websites based on perceived service quality (responsiveness, empathy and reliability), perceived risk (financial risk and time risk) and trust, and then to propose some targeted measures. A survey was conducted to collect data by means of questionnaires, and a total of 231 usable responses were gathered. Then the hypothesis model was tested using the Structural Equation Modeling(SEM). Results revealed that responsiveness, empathy, time risk and trust had significant impacts on customer satisfaction, whereas reliability and financial risk showed no effects on customer satisfaction. In addition, customer satisfaction and trust significantly influenced customer loyalty. The implications and limitations were discussed

    Flow Control at Satellite Gateways

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    Abstract-- Broadcast satellite networks are going play an important role in the global information infrastructure. Several systems including DirecWayfrom Hughes Network System use satellites to provide direct-to-user high speed Internet services. TCP works well in the terrestrial fiber networks but does not work well in satellite hybrid (satellite-terrestrial) networks. In this paper we analyze the problems that cause this dramatically degradedperformance. Based on the observation that it difficult for an end-to-end solution to solve these problems in this kind of hybrid networks, we propose a connection splitting based solution. A rate-based protocol is designed for the satellite connections and a flow control scheme at the satellite gateways (SGW) used to couple the two split connections together.Our simulation results shows that our scheme can maintain high utilization of the satellite link and improve fairness among the competing connections

    Bioactive conformational generation of small molecules: A comparative analysis between force-field and multiple empirical criteria based methods

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    <p>Abstract</p> <p>Background</p> <p>Conformational sampling for small molecules plays an essential role in drug discovery research pipeline. Based on multi-objective evolution algorithm (MOEA), we have developed a conformational generation method called Cyndi in the previous study. In this work, in addition to Tripos force field in the previous version, Cyndi was updated by incorporation of MMFF94 force field to assess the conformational energy more rationally. With two force fields against a larger dataset of 742 bioactive conformations of small ligands extracted from PDB, a comparative analysis was performed between pure force field based method (FFBM) and multiple empirical criteria based method (MECBM) hybrided with different force fields.</p> <p>Results</p> <p>Our analysis reveals that incorporating multiple empirical rules can significantly improve the accuracy of conformational generation. MECBM, which takes both empirical and force field criteria as the objective functions, can reproduce about 54% (within 1Å RMSD) of the bioactive conformations in the 742-molecule testset, much higher than that of pure force field method (FFBM, about 37%). On the other hand, MECBM achieved a more complete and efficient sampling of the conformational space because the average size of unique conformations ensemble per molecule is about 6 times larger than that of FFBM, while the time scale for conformational generation is nearly the same as FFBM. Furthermore, as a complementary comparison study between the methods with and without empirical biases, we also tested the performance of the three conformational generation methods in MacroModel in combination with different force fields. Compared with the methods in MacroModel, MECBM is more competitive in retrieving the bioactive conformations in light of accuracy but has much lower computational cost.</p> <p>Conclusions</p> <p>By incorporating different energy terms with several empirical criteria, the MECBM method can produce more reasonable conformational ensemble with high accuracy but approximately the same computational cost in comparison with FFBM method. Our analysis also reveals that the performance of conformational generation is irrelevant to the types of force field adopted in characterization of conformational accessibility. Moreover, post energy minimization is not necessary and may even undermine the diversity of conformational ensemble. All the results guide us to explore more empirical criteria like geometric restraints during the conformational process, which may improve the performance of conformational generation in combination with energetic accessibility, regardless of force field types adopted.</p
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