Sergentʼs White Line

The contextual separation of lateral white line patterns in chameleons

While many animals display different colour patterns that signal different messages, some species use various tactics to separate between colour and pattern displays. The common chameleon (Chamaeleo chamaeleon) is capable of rapidly changing and separating among displays of colour patterns and ornaments. We used chameleons to study the contextual role of separation among colour and pattern disp...

Single-ended Line Testing - a White Box Approach

A measurement, modelling and identification system is proposed to qualify a subscriber line with the constraint that only measurements can be conducted at the Central Office. The system uses the one-port scattering parameter as a base measurement of the loop. The time domain version of this scattering parameter will be pre-processed so that the features, which are the start, maximum and end pos...

Integrated system of white LED visible-light communication and power-line communication

Discovery of Photospheric Calcium Line-Strength Variations in the Dazd White Dwarf G29-38

Metals in the photospheres of white dwarfs with TeA between 12,000 and 25,000 K should gravitationally settle out of these atmospheres in 1Y2 weeks. Temporal variations in the line strengths of these metals could provide a direct measurement of episodic metal accretion. Using archival VLTand Keck spectroscopy, we find evidence that the DAZd white dwarf G29-38 shows significant changes in its Ca...

Rotation velocities of white dwarfs determined from the Ca II K line

We determine projected rotation velocities v sin i in DAZ white dwarfs, for the first time using the rotational broadening of the Ca II K line. The results confirm previous findings that white dwarfs are very slow rotators, and set even more stringent upper limits of typically less than 10 km s−1. The few exceptions include 3 stars known or suspected to be variable ZZ Ceti stars, where the line...