Elizabeth I dies and James VI of Scotland accedes to the English throne. Elizabeth I died childless so was succeeded by her cousin, James VI of Scotland, who henceforth assumed the title of James I of England as well.
T minus zero means out of time.. This comes from a countdown convention used in by both the American military and NASA. Generally, it is used when counting down to a major event that will happen at a specific time. Mathematically, T is time, minus whatever amount of time is left until the event happens.
Delta T. A triangle is the engineers symbol for delta and delta means change so if you were looking in a text book and you see a triangle it means change. The T represents temperature so delta t means change in temperature as was stated earlier.