Slugs and Thorns

Synapses , sea slugs , and psychiatry

This year’s Nobel Prize in physiology or medicine, announced on 9 October 2000, has gone to Arvid Carlsson, Paul Greengard, and Eric Kandel. The citation states that the prize is shared for pioneering discoveries in slow synaptic transmission, which are “crucial for an understanding of how the normal functioning of the brain and how disturbances in this signal can give rise to neurological and ...

Crown-of-thorns starfish

Figure 1. Crown-of-thorns starfish and their legacy. (A) A group of crown-of-thorns starfish converge on the remaining small piece of living coral tissue (lc) on the surface of a tabular coral (Acropora sp.) The other coral tissue has just been consumed by the starfish so that only the white skeleton remains (cs). (B) After crown-of-thorns starfish have removed the living coral tissue, the expo...

Stable Processes Have Thorns

Let X(t) be the symmetric α-stable process in Rd, α ∈ (0, 2), d ≥ 2. For f : (0, 1) → (0,∞) let D(f) be the thorn {x ∈ Rd : x1 ∈ (0, 1), |(x2, . . . , xd)| < f(x1)}. We give an integral criterion in terms of f for the existence of a random time s such that X(t) remains in X(s) +D(f) for all t ∈ [s, s+ 1).

Phototaxis of Dictyostelium discoideum Slugs

Representational Redescription for Sea Slugs

The paper discusses the Representational Redescription Hypothesis of Clark and Karmiloff-Smith [1]. This hypothesis -the ’RRH’ for short -has two main parts to it. Part one suggests that human cognitive development is a process involving the redescription of knowledge at increasing levels of abstraction. Part two is a claim about the true nature of thought. It states that representational redes...