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.
On a weather forecast map, a warm front is represented by a solid line with red semicircles pointing towards the colder air and in the direction of movement. Again, there is typically a noticeable temperature change from one side of the warm front to the other, much the same as a cold front. If colder air is replacing warmer air, it is a cold front, if warmer air is replacing cold air, then it is a warm front.