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.
Most strong tornadoes are associated with supercell thunderstorms. Supercells are long-lived severe thunderstorms which have updrafts and downdrafts that remain in balance. The winds are also rotating and rise into the storm called a mesocyclone. Only about 30% or less of supercell thunderstorms produce a tornado.