In this paper, we study the sensitivity and the topological property of periodic points for topologically transitive semi-flows on a metric space.

本文对度量空间上拓扑传递的连续半流，研究了其敏感依赖性及周期点集的拓扑性质。

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Using the design compression feature, this metric can be reduced to 11 MB of disk space, a savings of about 19 MB per mail file.

使用设计压缩功能，该标准将降低到 11 MB，每个邮件文件节省了近 19 MB。

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By current NASA estimates, a crewed mission to Mars needs to lift about twice the mass of the International space Station into space? Roughly 1.76 million LBS. (800 metric tons) of technology.

据美国宇航局最近的评估结果显示，载人登陆火星的任务需要把质量大约是国际空间站的两倍的物资送入太空，即大约176万磅(800吨)。

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The latter is a relatively new metric for advertisers in the online space, as most, until now, have relied on an ROI system based on impressions and clicks.

FORBES: Is "Ad Keeping" The Next Frontier?

Those who pay close attention to the sustainability space may be wondering right about now about the Global Reporting Initiative, which also uses a universal metric.

FORBES: Apples to Apples: Comparing Sustainability Projects' Cost And Environment Benefits