Willy Woelfli

Arctic East Siberia had a lower latitude in the Pleistocene

Remains of mammoths in Arctic East Siberia, where there is not sufficient sunlight over the year for the growth of the plants on which these animals feed, indicate that the latitude of this region was lower before the end of the Pleistocene than now. Reconstructing this geographic pole shift, we introduce a massive object, which moved in an extremely eccentric orbit and was hot from tidal work and solar radiation. Evaporation produced a disk-shaped cloud of ions around the Sun. This cloud partially shielded the solar radiation, producing the cold and warm periods characterizing the Pleistocene. The shielding depends on the inclination of Earths orbit, which has a period of 100,000 years. The cloud builds up to a point where inelastic particle collisions induce its collapse The resulting near-periodic time dependence resembles that of Dansgaard-Oeschger events. The Pleistocene ended when the massive object had a close encounter with the Earth, which suffered a one per mil extensional deformation. While the deformation relaxed to an equilibrium shape in one to several years, the globe turned relative to the rotation axis: The North Pole moved from Greenland to the Arctic Sea. The massive object split into fragments, which evaporated.

Beryllium-bombarded In0.53Ga0.47As and InP photoconductors with response times below 3 ps☆

Abstract High speed photoconductors, based on epitaxial In 0.53 Ga 0.47 As layers and semi-insulating InP, were integrated into broad band coplanar 50 ω microwave structures. To shorten the response times from the nanosecond to the picosecond range the devices were bombarded with beryllium ions. Implantation doses and profiled were optimized. With doses of 10 14 cm −2 and depths of 2 μm, response times as short as 2 ps and 3 ps were achieved for the In 0.53 Ga 0.47 As and InP photoconductors respectively.