0505 二战 新鲜的机经

zhoujy

Dendrochronology, the study of tree-ring records to glean information about the past, is possible because each year a tree adds a new layer of wood between the existing wood and the bark. In temperate and subpolar climates, cells added at the growing season's start are large and thin-walled, but later the new cells that develop are smaller and thick-walled; the growing season is followed by a period of dormancy. When a tree trunk is viewed in cross section, a boundary line is normally visible between the small-celled wood added at the end of the growing season in the previous year and the large-celled spring wood of the following year's growing season. The annual growth pattern appears as a series of larger and larger rings. In wet years rings are broad; during drought years they are narrow, since the trees grow less. Often, ring patterns of dead trees of different, but overlapping, ages can be correlated to provide an extended index of past climate conditions.
However, trees that grew in areas with a steady supply of groundwater show little variation in ring width from year to year; these "complacent" rings tell nothing about changes in climate. And trees in extremely dry regions may go a year or two without adding any rings, thereby introducing uncertainties into the count. Certain species sometimes add more than one ring in a single year, when growth halts temporarily and then starts again.
楼楼年轮求考古

Ulrica_K

感谢分享！               

AL7EN

bzy! 发表于 2018-5-5 17:54
https://www.nature.com/news/2008/080528/full/453569a.html

哥们牛逼

tiberries

感谢分享！               

AAA2015

感谢楼主的无私分享

billyisfragile!

有道题提到urban legend。
其他完全失忆。

也是CR 講一個urban legend要能在社會上流傳，必須要讓社會有一些甚麼甚麼(應該是要讓社會能感同身受甚麼的)，然後是利用聽到或是讀到的人的情緒的波動還有他們對於這個legend的信任(相信這個故事是對於某些危險的啟示) 問以上可以得到哪個選項中的結論

https://forum.chasedream.com/thread-1311298-1-1.html