A Novel Technique to Validate Dosimetry for Single-Isocenter Multiple-Target VMAT Stereotactic Radiosurgery

Each year, 170,000 cancer patients in the United States develop brain metastases. Many of them present with multiple small lesions. Historically, Linac-based stereotactic radiosurgery (SRS) was used to treat single solitary brain metastasis with a diameter of less than 3.0 cm, while whole brain radiation therapy (WBRT) was used to treat multiple brain metastases mainly as palliative therapy. Evidence-based practices reveal that WBRT results in poor treatment outcomes, with high local recurrence rates, decreased cognitive function, and even the onset of dementia. Recently, volumetric modulated arc therapy (VMAT) SRS has been tested as an alternative treatment to WBRT. Owing to its inherent complexity and high risk, it is imperative to perform rigorous testing prior to its clinical implementation. In this paper, we present a novel technique for dosimetry validation of VMAT SRS.

An empirical study of the effect of venture capital participation on the accounting information quality of IPO firms

Using a sample of IPO companies on the Shenzhen Small and Median Enterprise Board and the ChiNext Stock Market between 2005 and 2009, this paper analyzes the effect of venture capital participation on accounting information quality. We find that venture capitalists have a significant effect on earnings management, with reduced discretionary accruals before the expiration of the equity lock-up period and enhanced discretionary accruals after the expiration of the equity lock-up period. Our findings support the moral hazard hypothesis of venture capital, but not the certification/monitoring role of venture capital in IPOs. In addition, we find that venture capital plays a more important role in the earnings management of non-state-owned IPO companies than of state-owned companies.

Do business groups affect corporate cash holdings?Evidence from a transition economy

We examine whether business groups' influence on cash holdings depends on ownership. Group affiliation can increase firms' agency costs or benefit firms by providing an internal capital market, especially in transition economies characterized by weak investor protection and difficult external capital acquisition. A hand-collected dataset of Chinese firms reveals that group affiliation decreases cash holdings, alleviating the free-cash-flow problem of agency costs.State ownership and control of listed firms moderate this benefit, which is more pronounced when the financial market is less liquid. Group affiliation facilitates related-party transactions, increases debt capacity and decreases investmentcash-flow sensitivity and overinvestment. In transitional economies, privately controlled firms are more likely to benefit from group affiliation than statecontrolled firms propped up by the government.