“三连休”及因新休假制度显像的旅游建设提示

新休假制度生成了以“三连休”为代表的新概念并具有增加连休发生频率的特征,该制度的实施对旅游产生了“长线旅游减少、短线旅游增加”等方面的影响。讨论了以环城游憩带功能分层、开发关于旅游景区的区域票和关于旅行社的航空全国游套餐等措施应对的观点。     

对跆拳道运动员安静状态ECG特点的探讨

目的:探讨跆拳道运动员安静状态下心电图的一般特点及心律失常的发生率。方法:对30名青少年跆拳道运动员安静状态下心电图检出结果进行统计分析。结果:共检测出五种类型心律失常,跆拳道运动员ECG正常占46.6﹪,心律失常占53.4﹪。结论:跆拳道运动员心律失常表多为复合型。安静心电图异常带有普遍性,多数是对训练后的生理适应性反应。     

Market making with minimum resting times

We show how the supply of liquidity in order-driven markets is affected if limit orders (LOs) are forced to rest in the limit order book for a minimum resting time (MRT) before they can be cancelled. The bid-ask spread increases as the MRT increases because market makers (MMs) increase the depth of their LOs to protect them from being picked off by other traders. We also show that the expected profits of the MMs increase when the MRT increases. The intuition is as follows. As the MRT increases, there are two opposing forces at work. One, the longer the MRT, the more likely the LOs are to be filled and, on average, shares are sold at a loss. Two, because the depth of the posted LOs increases, the probability that the LO is picked off by other traders before the end of the MRT decreases. The net effect is that a longer MRT leads to a higher expected profit. We also show that the depth of LOs increases when the volatility of the price of the asset increases. Also, the depth of LOs increases when the arrival rate of market orders increases because it is less likely that LOs will be picked off by the end of the MRT. Finally, our model also makes predictions about the overall liquidity of the market. We show that MMs choose to supply the minimum amount of shares per LO allowed by the exchange because expected profits are maximised when liquidity provided is lowest.