The problem: Answer a question about this article:
Knots do not necessarily influence the stiffness of structural timber, this will depend on the size and location. Stiffness and elastic strength are more dependent upon the sound wood than upon localized defects. The breaking strength is very susceptible to defects. Sound knots do not weaken wood when subject to compression parallel to the grain.
Depending on the placement and size of a knot, what property of structural timber can be affected?
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The answer: stiffness

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Zhu Yousong, however, fared a lot worse than his ancestor Zhu Yuanzhang three centuries earlier. Beset by factional conflicts, his regime could not offer effective resistance to Qing forces, when the Qing army, led by the Manchu prince Dodo approached Jiangnan the next spring. Days after Yangzhou fell to the Manchus in late May 1645, the Hongguang Emperor fled Nanjing, and the imperial Ming Palace was looted by local residents. On June 6, Dodo's troops approached Nanjing, and the commander of the city's garrison, Zhao the Earl of Xincheng, promptly surrendered the city to them. The Manchus soon ordered all male residents of the city to shave their heads in the Manchu queue way. They requisitioned a large section of the city for the bannermen's cantonment, and destroyed the former imperial Ming Palace, but otherwise the city was spared the mass murders and destruction that befell Yangzhou.
When did the Hongguang Emperor leave Nanjing, having been defeated?
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The answer: late May 1645

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Although the number of base-pairs of DNA in the human genome has been known since the 1960s, the estimated number of genes has changed over time as definitions of genes, and methods of detecting them have been refined. Initial theoretical predictions of the number of human genes were as high as 2,000,000. Early experimental measures indicated there to be 50,000100,000 transcribed genes (expressed sequence tags). Subsequently, the sequencing in the Human Genome Project indicated that many of these transcripts were alternative variants of the same genes, and the total number of protein-coding genes was revised down to ~20,000 with 13 genes encoded on the mitochondrial genome. Of the human genome, only 12% consists of protein-coding genes, with the remainder being 'noncoding' DNA such as introns, retrotransposons, and noncoding RNAs.
Since when has the number of base pairs of DNA in the human genome been known?
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The answer: the 1960s

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Reginald DesRoches, a professor of civil and environmental engineering at Georgia Tech, pointed out that the massive damage of properties and houses in the earthquake area was because China did not create an adequate seismic design code until after the devastating 1976 Tangshan earthquake. DesRoches said: "If the buildings were older and built prior to that 1976 earthquake, chances are they weren't built for adequate earthquake forces."
When did China create a seismic design code for building?
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The answer:
1976