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Metal cesium (Cs) vapor, released at an altitude in the upper atmosphere, generates an artificial space plasma cloud with high electron density. It can act as a scatter to realize radio communication across an over-the-horizon distance. A full-life model of radio propagation via an artificial plasma cloud is established based on its space–time evolution in this article. In addition, this model is verified by the sounding data of the rocket release experiment carried out in the United States. The multipath effect of plasma cloud scattering is studied by using ray tracing, and then, the coherent bandwidth is estimated for this spatial channel. Also, the theoretical channel model of artificial plasma cloud is established by using its space–time evolution and atmospheric wind field parameters. Considering common modulation modes and receiver noise levels, the potential communication performance is evaluated by using the proposed channel model, such as the transmission rate, the bit error rate (BER), and the available time for building up and maintaining communication links. It is shown that the maximal communication rate is up to 200 kb/s, BER overall maintains below 10−7, and the available time for a single release is about 30–60 min; for the case of this article, they are release mass of 2–10 kg, communication distances of 400–1200 km, and radio frequencies of 30–70 MHz at the VHF band. This demonstrates that the artificial channel can propagate radio waves at a much higher frequency, wider bandwidth, and higher rate than those of HF communication. Hopefully, it could be a solution to overcome the intolerable shortcoming and adverse effects on HF communication due to ionospheric disturbances especially in cases of maritime, emergency, and minimum communications [ABSTRACT FROM AUTHOR]

In this paper, I show a generalisation of the negative relation of traditional accruals and percent accruals with future returns in 11 of 16 European countries. Positive abnormal returns from hedge portfolios on both accrual measures summarise the economic significance of this generalisation. The magnitude of returns obtained from traditional accruals is higher than that obtained from percent accruals, contrary to existing evidence from the U.S. capital market. The magnitude of the accrual effect on stock returns based on both accrual measures is stronger in countries with higher individualism, lower uncertainty avoidance, higher equity-market development, higher equity-market liquidity, lower transaction costs, higher analyst coverage, lower analyst optimism, and lower ownership concentration. In markets where minorities have legal protection against expropriation by corporate insiders and where accrual accounting is permitted, the accrual effect based only on percent accruals is positive. Earnings opacity does not appear to exhibit a significant influence. Overall, the evidence suggests that cross-country differences in culture, equity-market setting, analysts' research output, investor protection, and ownership structure play an important role in explaining variation on the magnitude of the accrual anomaly in Europe. [ABSTRACT FROM PUBLISHER]