Managing precision: how to use chronometers accurately at sea.

Marine chronometers, often considered precision instruments, proliferated in navigational practices during the nineteenth century. This paper examines their use in the hands of naval officers in the early-nineteenth century. It argues that both the instruments and their operators required careful management and regulation.

Benefits of Silvopastoral Systems for Keeping Beef Cattle.

The potential benefits of keeping Zebu cattle in silvopastoral systems are well described in tropical regions. In order to obtain information on European breeds of beef cattle () in temperate climate zones, individual records of body weight and welfare indicators were obtained from 130 beef cattle. These belonged to four herds and were randomly allocated to two contiguous plots: Silvopastoral Systems (SPS) and Open Pastures Systems (OPS).

Fluctuating Forces Induced by Nonequilibrium and Coherent Light Flow.

We show that mesoscopic coherent fluctuations of light propagating in random media induce fluctuating radiation forces. A hydrodynamic Langevin approach is used to describe the coherent light fluctuations, whose noise term accounts for mesoscopic coherent effects. This description-generalizable to other quantum or classical wave problems-allows us to understand coherent fluctuations as a nonequilibrium light flow, characterized by the diffusion coefficient D and the mobility σ, otherwise related by a Einstein relation.

Revealing the Topology of Quasicrystals with a Diffraction Experiment.

Topological properties of crystals and quasicrystals is a subject of recent and growing interest. This Letter reports an experiment where, for certain quasicrystals, these properties can be directly retrieved from diffraction. We directly observe, using an interferometric approach, all of the topological invariants of finite-length Fibonacci chains in their diffraction pattern.

Observing a scale anomaly and a universal quantum phase transition in graphene.

One of the most interesting predictions resulting from quantum physics, is the violation of classical symmetries, collectively referred to as anomalies. A remarkable class of anomalies occurs when the continuous scale symmetry of a scale-free quantum system is broken into a discrete scale symmetry for a critical value of a control parameter. This is an example of a (zero temperature) quantum phase transition.