Positive selection may refer to:
- Positive selection as an event during thymocyte maturation
- Directional selection, a particular mode or mechanism of natural selection.
Famous quotes containing the words positive and/or selection:
“Blessed be the inventor of photography! I set him above even the inventor of chloroform! It has given more positive pleasure to poor suffering humanity than anything else that has “cast up” in my time or is like to—this art by which even the “poor” can possess themselves of tolerable likenesses of their absent dear ones. And mustn’t it be acting favourably on the morality of the country?”
—Jane Welsh Carlyle (1801–1866)
“The books for young people say a great deal about the selection of Friends; it is because they really have nothing to say about Friends. They mean associates and confidants merely.”
—Henry David Thoreau (1817–1862)