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.
What caused the tornadoes? Warm, moist air from the Gulf of Mexico moved north until it encountered cold air brought south by the jet stream. When the warm and cold air from different altitudes come together, it creates wind shear and circular air motions that lead to a tornado. The air from the south was unusually warm and moist for this time of year, according to Stu Ostro, a senior meteorologist at the Weather Channel.