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.
This year's tornado season has been very wimpy, said Chattanooga's WRCB-TV Channel 3 Chief Meteorologist Paul Barys. It's about as wimpy as it's ever been.. The reason it's been so low is we've had so much cold air, he said. It's also been an exceptionally dry spring, Barys said.