It can become concentrated in small areas and then disappear.

VOA: special.2009.12.30

She had long, thin limbs and a small, very concentrated face whose severe features were drawn dramatically forward, culminating in a sharply pointed nose.

NEWYORKER: The Valetudinarian

But others point out that while this is the case, the pyres are concentrated in small areas rather than spread throughout the nation.

BBC: Foot-and-mouth pyres: Dioxin danger?

Yet the nature of m-commerce transactions, most relatively small in size and concentrated on items that are time- or location-sensitive, will limit the overall size of the m-commerce market.

ECONOMIST: Waves of the future