How often does the Unruh-DeWitt detector click beyond four dimensions?

We analyse the response of an arbitrarily-accelerated Unruh-DeWitt detector coupled to a massless scalar field in Minkowski spacetimes of dimensions up to six, working within first-order perturbation theory and assuming a smooth switch-on and switch-off. We express the total transition probability as a manifestly finite and regulator-free integral formula. In the sharp switching limit, the transition probability diverges in dimensions greater than three but the transition rate remains finite up to dimension five. In dimension six, the transition rate remains finite in the sharp switching limit for trajectories of constant scalar proper acceleration, including all stationary trajectories, but it diverges for generic trajectories. The divergence of the transition rate in six dimensions suggests that global embedding spacetime (GEMS) methods for investigating detector response in curved spacetime may have limited validity for generic trajectories when the embedding spacetime has dimension higher than five.Comment: 30 pages. v3: presentational improvement. Published versio

Examining evidence based resistance plus balance training in community-dwelling older adults with complex health care needs: Trial protocol for the Muscling Up Against Disability project

Available online 6 October 2016Abstract not availableJustin W.L. Keogh, Tim Henwood, Paul Gardiner, Anthony Tuckett, Brent Hodgkinson, Kevin Rous

Mortality Model for a Perennial Grass in Australian Semi-Arid Wooded Grasslands Grazed by Sheep

Grazing of sheep in marginal semi-arid environments is risky because grazing appears to predispose grass plants, especially palatable species, to sudden death (Hodgkinson, 1994; 1995). These early observations were based on a preliminary analysis of perennial grass survival in a single drought and supported the concept of tactical grazing proposed by Westoby et al. (1989) as a preferred management. Later this idea was developed by suggesting the existence of critical thresholds for perennial grass survival, which when crossed, collapses grass populations (Hodgkinson, 1994). Here we examine the relationship between mortality of a palatable perennial grass, Thyridolepis mitchelliana, and a number of variables measured during a 10-year period

Sheep Grazing During Drought Collapses the Perennial Grass Resource in Australian Semiarid Wooded Grasslands

Grazing of sheep in arid grasslands is risky; sudden shifts to lower functional states may occur when the ecosystem is stressed (Scheffer et al., 2001). To avoid the stresses that shift states, easy-to-recognise critical thresholds need to be identified (Westoby et al., 1989). Preliminary analysis of perennial grass survival in a drought indicated a critical threshold based on co-occurrence of drought and grazing. Crossing this threshold collapses grass populations (Hodgkinson, 1994). Here we examine the relationships between basal area change and rainfall and grazing levels based on a 10-year period and propose a management guideline

Smart cable for design of high density metallic cross connect systems

The present invention to provide a smart cable system for high density metallic cross connect systems. In particular, this invention relates to the physical structure of cables and associated hardware needed to form the smart cable system for interconnecting cards in shelves and racks of high density metallic cross connect switching systems. This invention provides the cable installer the ability to connect cables to cards with minimal errors by using visual indicators. The visual indicators guide the cable installer such that he/she can properly install the cables into the appropriate connectors. The present invention also provides a means for detecting when and where the cables are connected within the cross connect system

An optical fiber hydrogen sensor using a palladium-coated ball lens

A self-referenced optical fiber refractometer using a ball lens as a sensor head has been developed and characterized. A 350-μm ball lens created at the tip of a single mode fiber has been coated with a 40-nm optically thin layer of palladium that reacts with hydrogen to form a hydride, which has a lower reflectivity than pure palladium. Optical reflectance measurements from the tip of the ball lens were performed to determine the hydrogen response. The change in reflectivity is proportional to the hydrogen concentration in the range 0% to 1% hydrogen in air with a detection limit down to 10 ppm (1σ) in air. This technique offers a simple sensor head arrangement, with a larger sampling area (~40 times) than a typical single-mode fiber core. A statistical image analysis of a palladium film, with cracks created by accelerated failure, confirms that the anticipated sensor area for a ball lens sensor head has a more predictable reflectivity than that of a bare fiber core