Topologists have known for almost three decades that there are exactly four regular homotopy classes for marked tori immersed in 3D Euclidean space. Instances in different classes cannot be smoothly transformed into one another without introducing tears, creases, or regions of infinite curvature into the torus surface. In this paper, a quartet of simple, easy-to-remember representatives for the...

Epidemiology has features that resemble those of the traditional liberal arts. This makes it fit both for inclusion in an undergraduate curriculum and as an example in medical school of the continuing value of a liberal education. As a "low-technology" science, epidemiology is readily accessible to nonspecialists. Because it is useful for taking a first look at a new problem, it is applicable t...

The culmination of artist Aya Ben Ron's six-month residence at the Wellcome Trust in London has been hanging dramatically in the main atrium of the building throughout the summer. The 25-metre-long " Hanging " glistens with kaleidoscopic, colourful images and patterns but on closer scrutiny holds a darker message. The colourful images are revealed to comprise images of various human diseases an...