"If something is obstructing the flow of that radiation, for example a weapon, the device will highlight that object, " said Commissioner Raymond Kelly, who described the device Wednesday in a speech at the Waldorf-Astoria Hotel.

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Richard Hamilton of Columbia University had previously realised the usefulness of this heat-flow model but became unstuck when he found that, under this transformation, the object may stretch out to form singularities spikes that could not be easily manipulated into a sphere.

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