Can a Carnot cycle ever be totally reversible?

Can viruses ever be useful?

M ost of the terms used for computer viruses arc metaphors: they have a largely medical origin, and are seductive if not literally sexy. The very real worries WC have about AIDS, for example, no doubt colour the way we talk about computer viruses. At the extreme, abstractly viruses arc clearly just algorithms, and like any other algorithm they arc good for some things and not good for others. T...

Poset Limits Can Be Totally Ordered

S. Janson [Poset limits and exchangeable random posets, Combinatorica 31 (2011), 529–563] defined limits of finite posets in parallel to the emerging theory of limits of dense graphs. We prove that each poset limit can be represented as a kernel on the unit interval with the standard order, thus answering an open question of Janson. We provide two proofs: real-analytic and combinatorial. The co...

Burst Imaging—Can It Ever Be Useful in the Clinic?

Burst is an ultra-rapid imaging sequence that works by excitation of magnetization using a series of regularly spaced, low flip-angle pulses, applied at the same time as a gradient in the read direction. In the original concept, this gradient is constant, and multiple echoes are refocused under a constant-read gradient. This article brings together the previous literature on the subject, placin...

Can hospital mortality comparisons ever be fit for purpose?

Can snails ever be effective and safe biocontrol agents ?

The use of snails as biocontrol agents against other snails and against aquatic weeds is reviewed, evaluating their success and their impacts on non-target organisms. The predatory snail Euglandina rosea (and other species), although widely used against Achatina fulica (the giant African land snail) on Pacific and Indian Ocean islands, has not been shown to control A. fulica but has seriously i...