Whether and when did bitcoin sentiment matter for investors?Before and during the COVID‑19 pandemic

Using a wavelet coherence approach,this study investigates the relationship between Bitcoin return and Bitcoin-specific sentiment from January 1,2016 to June 30,2021,covering the COVID-19 pandemic period.The results reveal that before the pandemic,sentiment positively drove prices,especially for relatively higher frequencies(2–18 weeks).During the pandemic,the relationship was still positive,but interestingly,the lead-lag relationship disappeared.Employing partial wavelet tools,we factor out the number of COVID-19 cases and deaths and the Equity Market Volatility Infectious Disease Tracker index to observe the direct relationship between a change in sentiment and return.Our results robustly reveal that,before the pandemic,sentiment had a positive effect on return.Although positive coherence still existed during the pandemic,the lead-lag relationship disappeared again.Thus,the causal relationship that states that sentiment leads to return can only be integrated into short-term trading strategies(up to six weeks frequency).

曲美他嗪治疗冠心病的临床疗效

目的观察曲美他嗪治疗冠心病伴慢性心力衰竭的临床疗效。方法120例冠心病合并慢性心力衰竭的患者,随机分为对照组(常规治疗)和曲美他嗪组各60例(常规治疗加曲美他嗪20mg,3次/d),观察3个月。结果曲美他嗪组的心衰缓解情况、超声心动图的心功能指标均显著优于对照组(P<0.05)。结论常规药物联合曲美他嗪治疗冠心病伴慢性心力衰竭是一种疗效确切,安全简便的方法,值得临床推广使用。