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 this map from the National Climatic Data Center shows, other global tornado hotspots include Bangladesh, South Africa, and Europe: On April 26, 1989, the deadliest tornado ever struck Bangladesh, killing about 1,300 people, injuring 12,000, and leaving 80,000 homeless.