专家学者对此现象进行了一系列的研究，由于研究时间短，尚没有成型的理论可供借鉴，因此，城中村更新改造的理论研究还处于探索阶段。

Because the time of research is very short, and no shaped theory to be taken. So, the theory of the City Village renewal and renovation fundamental research also is at the stage of exploration.

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而此次研究观察的是断断续续的，但是不比正常睡眠时间短或强度弱的睡眠。

This study looked at sleep that was fragmented, but not shorter or less intense than normal for the mice.

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这四项研究中，患者随访的时间都比通常认为的评价药物暴露是否会导致癌症风险所需的时间短。

The duration of patient follow-up in all four studies was shorter than what is generally considered necessary to evaluate for cancer risk from drug exposure.

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