Coronal emission lines as thermometers

Coronal emission line intensities are commonly used to measure electron temperatures using emission measure and/or line ratio methods. In the presence of systematic errors in atomic excitation calculations and data noise, the information on underlying temperature distributions is fundamentally limited. Increasing the number of emission lines used does not necessarily improve the ability to discriminate between different kinds of temperature distributions.Comment: Accepted by ApJ, November 200

Evaluation of the South Australian default 50 km/h speed limit

On 1 March 2003 the default urban speed limit in South Australia was reduced from 60 km/h to 50 km/h. On-road speeds just before the default limit was introduced were compared with speeds a year later. The numbers of casualty crashes and casualties in the year before the default limit was introduced were compared with the corresponding numbers in the first year that the default limit was in effect. On roads where the speed limit was reduced from 60 km/h to 50 km/h, average vehicle speeds decreased by 2.3 km/h and casualties by 24 per cent. On roads where the speed limit remained at 60 km/h, average vehicle speeds decreased by 0.9 km/h and casualties by 7 per cent.C.N. Kloeden, J.E. Woolley and A.J. McLea

Quantifying Device Usefulness -- How Useful is an Obsolete Device?

Obsolete devices add to the rising levels of electronic waste, a major environmental concern, and a contributing factor to climate change. In recent years, device manufacturers have established environmental commitments and launched initiatives such as supporting the recycling of obsolete devices by making more ways available for consumers to safely dispose of their old devices. However, little support is available for individuals who want to continue using legacy or 'end-of-life' devices and few studies have explored the usefulness of these older devices, the barriers to their continued use and the associated user experiences. With a human-computer interaction lens, this paper reflects on device usefulness as a function of utility and usability, and on the barriers to continued device use and app installation. Additionally, the paper contributes insights from a sequel study that extends on prior work evaluating app functionality of a 'vintage' Apple device with new empirical data on app downloadability and functionality for the same device when newly classified as 'obsolete'. A total of 230 apps, comprising the top 10 free App Store apps for each of 23 categories, were assessed for downloadability and functionality on an Apple iPad Mini tablet. Although only 20 apps (8.7%) could be downloaded directly onto the newly obsolete device, 143 apps (62.2%) could be downloaded with the use of a different non-legacy device. Of these 163 downloadable apps, 131 apps (com-prising 57% of all 230 apps and 80.4% of the downloadable apps) successfully installed, opened, and functioned. This was a decrease of only 4.3% in functional apps (of the 230 total apps) compared to the performance of the device when previously classified as 'vintage'.Comment: 10 pages, 3 figures, 1 tabl

Further evaluation of the South Australian default 50 km/h speed limit

On 1 March 2003 the default urban speed limit in South Australia was reduced from 60 km/h to 50 km/h. On-road speeds just before the default limit was introduced were compared with speeds one and three years later. The number of casualty crashes and casualties in the three years before the default limit was introduced were compared with corresponding numbers in the three years after the default limit came into effect. On roads where the speed limit was reduced from 60 km/h to 50km/h, average speeds decreased by 3.8km/h after three years and casualty crashes fell by 23 per cent. On roads where the speed limit remained at 60 km/h, average vehicle speeds decreased by 2.1 km/h after three years and casualty crashes fell by 16 per cent.C.N. Kloeden, J.E. Woolley and A.J. McLea

Quantum electrodynamics in modern optics and photonics: tutorial

One of the key frameworks for developing the theory of light–matter interactions in modern optics and photonics is quantum electrodynamics (QED). Contrasting with semiclassical theory, which depicts electromagnetic radiation as a classical wave, QED representations of quantized light fully embrace the concept of the photon. This tutorial review is a broad guide to cutting-edge applications of QED, providing an outline of its underlying foundation and an examination of its role in photon science. Alongside the full quantum methods, it is shown how significant distinctions can be drawn when compared to semiclassical approaches. Clear advantages in outcome arise in the predictive capacity and physical insights afforded by QED methods, which favors its adoption over other formulations of radiation–matter interaction