Tungsten current price was transformed yearly to its constant price since 1900, which is roughly decomposed into four components as trend, cycle, impact and random. The core prices, consisting of the trend and the cyc...Tungsten current price was transformed yearly to its constant price since 1900, which is roughly decomposed into four components as trend, cycle, impact and random. The core prices, consisting of the trend and the cycle, present regularities that a long-run cycle is embedded within two major cycles, and major cycle is composed of low-price period and high-price period, along with the rapid rise into a tower, and along with deep down into next trough; three sharply upward shocks occur by the events in a tower. Fluctuations in prices trend to slow cycles and expand the bands. It can be expected that tungsten price will highly stand over 17 a, and is is a advice that reducing production and restricting export maybe maintain a high price level.展开更多
基金Project(2013ZK2001)supported by the Major Soft Science Program of Hunan Provice,ChinaProjects(1382ZD024,13BGL105)supported by the National Social Science Foundation of China
文摘Tungsten current price was transformed yearly to its constant price since 1900, which is roughly decomposed into four components as trend, cycle, impact and random. The core prices, consisting of the trend and the cycle, present regularities that a long-run cycle is embedded within two major cycles, and major cycle is composed of low-price period and high-price period, along with the rapid rise into a tower, and along with deep down into next trough; three sharply upward shocks occur by the events in a tower. Fluctuations in prices trend to slow cycles and expand the bands. It can be expected that tungsten price will highly stand over 17 a, and is is a advice that reducing production and restricting export maybe maintain a high price level.
文摘目的:系统评价经导管主动脉瓣置换术后新发心房颤动(房颤)的发生率及预测因子。方法:全面检索Pub Med、Springer、Elsevier-SDOL、EMbase、SSCI、CNKI、VIP、中国生物医学文献数据库、万方数据资源系统在2009-01至2016-01期间发表的主动脉瓣置换术后新发房颤的研究文献。利用疾病患病率或发病率质量准则评价文献质量,运用Comprehensive Meta Analysis软件版本2.0进行Meta分析。结果:最终纳入14个研究,其中4个为多中心随机对照研究,共包含6 626例接受经导管主动脉瓣膜置换术的严重主动脉瓣狭窄患者。术后新发房颤的发生率为11.1%[95%可信区间(CI):10.3~11.9]。经导管主动脉瓣膜置换术后发生新发房颤的独立预测因子包括:经心尖途径[比值比(OR)=2.16,95%CI:1.58~2.94,P<0.001]、手术相关心脏事件(OR=1.59,95%CI:1.08~2.36,P=0.01)、手术相关出血事件(OR=1.56,95%CI:1.00~2.45,P=0.04)、心房过大(每增加1mm/m^2,OR=1.21,95%CI:1.09~1.34,P<0.001)。结论:经导管主动脉瓣置换术后新发房颤的发生率较高,且可能导致严重的临床不良事件。深入研究其预测因子有利于提高主动脉瓣置换术后的安全性。
