In general, the idea is to consume only the amount of phenylalanine that's necessary for normal growth and body processes, but no more.

CNN: Phenylketonuria (PKU)

What are the small ways you can lead (and I do mean, lead, not trick) folks, following their own self-interest and in the course of their normal activity, to take the necessary steps toward more sustainable operations and personal behavior?

FORBES: The Birds and Bees of Sustainability

He said it was rewarding behaviour which should be considered normal and questioned whether it was necessary to go as far as New York.

BBC: Skegness Academy

Those with a high result would return for frequent screening and checks (and treatment if necessary), while those with normal results could wait until their early 50s for their next PSA test.

BBC: Prostate cancer: Case to test men in their 40s

That appears not to be necessary after NYSE said its building and floor are capable of handling a normal trading session.

FORBES: Stock Market To Reopen Wednesday After Hurricane Sandy Hammers New York

This questioning is necessary for restoring order in a world where the new normal demands different thinking and responses.

FORBES: Confusion can be a good thing (and will lead to prosperity)

Ms Roll said the recycling centre next door was still operating as normal and Grundon was prepared to assist the fire service if necessary.

BBC: Fire at Beenham

Extra gas - including supplies from Belgium and Norway - was necessary to meet rising demand after a 30% rise on normal seasonal use during the cold snap.

BBC: Snow and ice leads to travel delays and school closures

Work by Dr. Gershon and others has shown that serotonin is necessary for the repair of cells in the liver and lungs, and plays a role in normal heart development and bone-mass accumulation.

WSJ: A Gut Check for Many Ailments