In addition to the mean meridional Hadley circulation, there also exist zonal overturning circulations that contribute to the meteorology and climatology of the tropics. Together, these overturning circulations are commonly referred to as the Walker circulation. In this section, we first explore the history and basic structure of the Walker circulation. Later, we reintroduce the shallow water e...

John Walker Barber-Lomax, always known to family and friends alike as Jack, and to colleagues as B-L, died on 13 April. He was born on 4 December 1914, near Bolton, Lancashire. After Charterhouse and Caius College, Cambridge, he proceeded to St Thomas' Hospital for a medical training but changed course and went up to the Liverpool veterinary school where he took the Golding prize in veterinary ...

Paediatricians were surveyed about baby walker knowledge, attitudes, and practice. Advising about walkers was associated with working in community paediatrics, treating walker related injuries, knowledge about walkers, and positive attitudes towards walker health promotion. Greater knowledge about walkers was associated with more negative attitudes to walkers. Educating paediatricians and paren...

One major challenge in nanotechnology is to transport a nano-scale object from one location to another on a nano-structure. Molecular walkers are nano-machines designed for this task they are structures that can attach and move on some substrate. There have been several preliminary experiments for DNA walkers. However, none of these walker designs are “programmable”. These walkers either requir...

Motivated by a biased diffusion of molecular motors with the bias dependent on the state of the substrate, we investigate a random walk on a one-dimensional lattice that contains weak links (called "bridges") which are affected by the walker. Namely, a bridge is destroyed with probability when p the walker crosses it; the walker is not allowed to cross it again and this leads to a directed moti...

We consider a model introduced by Baker et al. [Phys. Rev. E 88, 042113 (2013)] of a single lattice random walker moving on a domain of allowed sites, surrounded by blocked sites. The walker enlarges the allowed domain by eroding the boundary at its random encounters with blocked boundary sites: attempts to step onto blocked sites succeed with a given probability and convert these sites to allo...

Consider a walker performing a random walk in an i.i.d. random environment, and assume that the walker tells us at each time the environment it sees at its present location. Given this history of the transition probabilities seen from the walker but not its trajectory can we reconstruct the law of the environment? We show that in a one-dimensional environment, the law of the environment can be ...

Weakening of the tropical overturning circulation in a warmer world is a robust feature in climate models. Here an idealized representation of ocean heat flux drives a Walker cell in an aquaplanet simulation. A goal of the study is to assess the influence of the Walker circulation on the magnitude and structure of climate feedbacks, as well as to global sensitivity. We compare two CO2 perturbat...

The eponym “Walker Circulation” refers to a concept used by atmospheric scientists and oceanographers in providing a physical explanation for the El Niño–Southern Oscillation phenomenon, whereas the eponym “Yule–Walker equations” refers to properties satisfied by the autocorrelations of an autoregressive process. But how many statisticians (or, for that matter, atmospheric scientists) are aware...