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Author Question: In the regression model Yi = 0 + 1Xi + 2Di + 3(Xi Di) + ui, where X is a continuous variable and D ... (Read 70 times) |
The modern decimal position system was the invention of the Hindus (around 800 AD), involving the placing of numerals to indicate their value (units, tens, hundreds, and so on).
There are more nerve cells in one human brain than there are stars in the Milky Way.
Barbituric acid, the base material of barbiturates, was first synthesized in 1863 by Adolph von Bayer. His company later went on to synthesize aspirin for the first time, and Bayer aspirin is still a popular brand today.
In 1885, the Lloyd Manufacturing Company of Albany, New York, promoted and sold "Cocaine Toothache Drops" at 15 cents per bottle! In 1914, the Harrison Narcotic Act brought the sale and distribution of this drug under federal control.
Interferon was scarce and expensive until 1980, when the interferon gene was inserted into bacteria using recombinant DNA technology, allowing for mass cultivation and purification from bacterial cultures.