Random Pure Gaussian States and Hawking Radiation.

A black hole evaporates by Hawking radiation. Each mode of that radiation is thermal. If the total state is nevertheless to be pure, modes must be entangled.

Information transmission without energy exchange.

We show that it is possible to use a massless field in the vacuum to communicate in such a way that the signal travels arbitrarily slower than the speed of light and such that no energy is transmitted from the sender to the receiver. Instead, the receiver has to supply a signal-dependent amount of work to switch his detector on and off. This type of communication is related to Casimir-like interactions, and it is made possible by dimension-and curvature-dependent subtleties of Huygens' principle.

The decline in visual acuity in elderly people with healthy eyes or eyes with early age-related maculopathy in two Scandinavian population samples.

Purpose: This study aimed to analyse the decline in visual acuity (VA) during normal ageing in two Scandinavian population samples of subjects aged ≥ 70 years and to study the age-specific decline in VA in eyes with early age-related maculopathy (ARM).

Methods: We carried out a cross-sectional analysis of data pertaining to VA in the better eye in one population sample from Oulu (OU), Finland (aged 70-82 years) and a second population sample from Gothenburg (GG), Sweden (aged 82 or 88 years). The change in VA with age was evaluated in healthy eyes (OU, n = 119; GG, n = 40) and in eyes with early ARM (OU-ARM, n = 22; GG-ARM, n = 114) using linear regression or logistic regression.

Final pH affects the interference capacity of naturally occurring oral Lactobacillus strains against mutans streptococci.

Objectives: To establish the effects of three factors: previous caries experience; colonization of Streptococcus mutans; and final pH on autologous lactobacilli-mediated inhibition against a panel of mutans streptococci in young subjects with different caries experiences.

Design: The inhibition capacity was determined by the use of the agar overlay method and the final pH in culture medium was measured after 20 h. Using a logistic regression model, the risk of having an incomplete lactobacilli-mediated inhibition was calculated.

Predictors for work ability and disability in men and women with low-back or neck problems.

In many countries back and neck problems are the most common reason for work incapacity. Numerous studies have looked for reliable predictors of return to work (RTW) or not return to work (NRTW) for those incapacitated, but with few exceptions their predictive and detective ability has been limited. We aimed to perform a comparative study of various commonly used health measures ability to predict RTW or NRTW in a cohort of men and women sick-listed for more than 28 days due to low-back pain (LBP) or neck pain (NP).