Class A (type D) CpG ODNs (CpG-A ODNs) contain a central palindromic phosphodiester (PO) CpG sequence and a PS-modified 3â poly-G tail. The poly G tails form intermolecular tetrads that result in high molecular weight ordered structures.
Why does a tornado form when cold and hot air meet? The collision of warm and cold air is not the direct cause of a tornado, nor is it absolutely necessary. When a cold air mass pushes into a warm air mass (this is called a câ¦old front) the warmer, less dense air is forced upwards.
As we've shown in a number of other articles, tornadoes are like snowbirdsâthey winter in the South. Even there, cool and dry is the name of the game more often than not in the weeks around the new year when tornado tallies reach their minimum. Cold-season tornadoes are generally limited, but larger events happen.