论文部分内容阅读
数学奥林匹克高中训练题(269)
【出 处】
：
中等数学
【发表日期】
：
2021年11期
其他文献
As a multicellular organism,rice flourishes relying on gene expression diversity among cells of various functions.However,cellular-resolution transcriptome features are yet to be fully recognized,let alone cell-specific transcriptional responses to enviro
Southern East Asia,including Guangxi and Fujian provinces in China,is home to diverse ethnic groups,languages,and cultures.Previous studies suggest a high complexity regarding population dynamics and the history of southern East Asians.However,large-scale
Enhancers are critical cis-regulatory elements that regulate spatiotemporal gene expression and control cell fates.However,the identification of enhancers in native cellular contexts still remains a challenge.Here,we develop an inducible CRISPR activation
草木皆兵的故事出自古代著名战役“淝水之战”.一千七百多年前,东晋大将谢玄、谢石率领八万兵马,在淝水八公山战胜前秦王苻坚的八十万大军.后人根据这段史实,造出了成语“风声鹤唳,草木皆兵”.
期刊
第51届IMO预选题几何部分第一题为:rn题1 设锐角△ABC边BC、CA、AB的高的垂足分别为D、E、F,直线EF与△ABC的外接圆的一个交点为P,直线BP与DF交于点Q.证明:AP =AQ.[1]rn笔者在证明此题时将点C一侧补全,调整了字母顺序,得到题2.rn题2 设锐角△ABC边BC、CA、AB的高的垂足分别为D、E、F,直线EF与△ABC的外接圆的两个交点分别为M、N(M在劣弧(AB)上),直线BM与DF、CN与DE分别交于点P、Q.证明:PQ∥BC.
期刊
Antibody upstream sequence diversity and its biological implications revealed by repertoire sequenci
The sequence upstream of the antibody variable region (antibody upstream sequence[AUS]) consists of a 5\'untranslated region (5\'UTR) and a preceding leader region.The sequence variations in AUS affect antibody engineering end PCR based antibody quant
决赛rn1.对某些正整数n＞m,数n既可以表示为2021个加数的和,其中,每个加数均为m的非负整数次方幂数,又可以表示为2 021个加数的,其中,每个加数均为m+1的非负整数次方幂数.试问:对于怎样的最大的m有此可能(即使只存在一个n＞m)?
期刊
Interception,degradation and contributions of terrestrial organic carbon obtained from lignin analys
Understanding the fate of terrestrial organic carbon (OC) in a cascade impoundment system is critical for recognizing the role of carbon sink for reservoirs.Surface sediments collected from eight cascade reservoirs across the Wujiang River,southwestern Ch
Nitrogen is a key element essential for plant growth and crop pro-duction,and the improvement of the nitrogen use efficiency (NUE) of crops largely contributes to yield production.The improvement of NUE is a major challenge in agriculture,not only for red
期刊