By “polar cliff” we mean the steep increase in the ionization density observed in the morning sector of the polar ionosphere. Here the properties of this remarkable feature are investigated. The data set consists of electron density and temperature measurements obtained by the Dynamics Explorer 2 satellite. Only data recorded in the Northern Hemisphere winter are considered (solar zenith angle≥...

The survival probability of a particle diffusing in the two-dimensional domain x > 0 near a "windy cliff" at x = 0 is investigated. The particle dies upon reaching the edge of the cliff: In addition to diffusion, the particle is influenced by a steady "wind shear" with velocity v(x,y)=vsign (y)~, i.e., no average bias either toward or away from the cliff. For this semi-infinite system, the part...

The retreat of chalk cliffs fringing the eastern English Channel contributes shingle to the beaches which helps to protect the cliffs and slow down erosion. Conversely, cliff retreat endangers settlements and infrastructure on the clifftop. Rates of retreat have been calculated by a variety of methods over the past century, but no attempt has been made to provide a complete coverage that allows...

In this paper we describe Artificial Intelligence as research that moves along two different axes: humancompatible knowledge and machine-compatible proceasing. An analysis of computer chess research along these dimensions shows that AI more and more diverges into an engineering branch and a cognitive branch. As an explanation, we offer a hypothesis about the dependency of research effort on the...

Twas a dangerous cliff, they freely confessed, Though to walk near its crest was so pleasant, But, over its terrible edge there had slipped A duke and full many a peasant; So the people said something would have to be done, But their projects did not at all tally. Some said: "Put a fence round the edge of the cliff." Others said: An ambulance down in the valley." Joseph Malines Prevention and C...

We analyse the statistical pattern of seismicity before a 1-2 10 m chalk cliff collapse on the Normandie ocean shore, Western France. We show that a power law acceleration of seismicity rate and energy in both 40 Hz-1.5 kHz and 2 Hz-10kHz frequency range, is defined on 3 order of magnitude, within 2 hours from the collapse time. Simultaneously, the average size of the seismic events increases t...

The south-west coast of the Isle of Wight (see Figure 4.1 for general location) is geomorphologically rich in features of interest. It contains examples of most of the cliff types undergoing active erosion described from other GCR sites. The site demonstrates well how coastal processes have produced different cliff forms related not only to variations of lithology and geological structure, but ...

Between Ridge Cliff, to the east of Seatown, to Lyme Regis, there are four main cliffed areas, Ridge Cliff, Golden Cap, Cain's Folly and Black Ven, separated by valleys at Seatown, St Gabriel's Water and Charmouth (see Figure 4.1 for general location, and Figure 4.11). There are two pocket-type beaches, the larger between Golden Cap and Lyme Regis, the smaller to the east of Golden Cap at Seato...