我国上市公司首次披露股权激励计划的市场反应分析

本文首次以《上市公司股权激励管理办法》颁布以来沪深两市首次披露股权激励计划的上市公司作为研究对象,运用事件研究法计算超额收益的方式,检验了股权激励计划披露前后超额收益率的变动情况.研究发现,在股权激励计划披露后,证券市场有显著的正面反应;在股权激励计划披露前34天的短时窗内证券市场有不显著的正面反应,在披露前60天到90天的长时窗内,证券市场有负面反应.     

The shadow and observation appearance of black hole surrounded by the dust field in Rastall theory

In the context of Rastall gravity, the shadow and observation intensity casted by the new Kiselev-like black hole with dust field have been numerically investigated. In this system, the Rastall parameter and surrounding dust field structure parameter have considerable consequences on the geometric structure of spacetime. Considering the photon trajectories near the black hole, we investigate the variation of the radii of photon sphere, event horizon and black hole shadow under the different related parameters. Furthermore, taking into account two different spherically symmetric accretion models as the only background light source, we also studied the observed luminosity and intensity of black holes. For the both spherical accretions background, the results show that the decrease or increase of the observed luminosity depends on the value range of relevant parameters, and the promotion effect is far less obvious than the attenuation effect on the observed intensity. One can find that the inner shadow region and outer bright region of the black hole wrapped by infalling accretion are significantly darker than those of the static model, which is closely related to the Doppler effect. In addition, the size of the shadow and the position of the photon sphere are always the same in the two accretion models, which means that the black hole shadow depend only on the geometry of spacetime, while the observation luminosity is affected by the form of accretion material and the related spacetime structure.