though only at too high a level of generality to provide regulators with the needed guidance.32 For example, Professor Mark Sagoff suggests agencies should regulate up to the “knee of the [cost] curve,”33 which is “the point at which the cost of controlling the next incremental unit of pollution begins to increase rapidly,” and returns to the environment rapidly diminish per dollar spent.34 But...

The Internet is awash with a wealth of maps and spatial imagery, some crude and basic, some refined and highly developed. The availability of maps and imagery of Africa over the Internet and the sophistication of the methods used to display such spatial images will almost certainly increase and so continue to revolutionise the way maps and remotely-sensed images are marketed and delivered world...

The two main stability results for nearly-integrable Hamiltonian systems are revisited: Nekhoroshev theorem, concerning exponential lower bounds for the stability time (effective stability), and KAM theorem, concerning the preservation of a majority of the nonresonant invariant tori (perpetual stability). To stress the relationship between both theorems, a common approach is given to their proo...