Computing is a high-level process of a physical system. Recent interest in non-standard computing systems, including quantum and biological computers, has brought this physical basis of computing to the forefront. There has been, however, no consensus on how to tell if a given physical system is acting as a computer or not; leading to confusion over novel computational devices, and even claims that every physical event is a computation. In this paper we introduce a formal framework that can be used to determine whether or not a physical system is performing a computation. We demonstrate how the abstract computational level interacts with the physical device level, drawing the comparison with the use of mathematical models to represent physical objects in experimental science. This powerful formulation allows a precise description of the similarities between experiments, computation, simulation, and technology. We give conditions that must be satisfied in order for computation to be occurring, and apply these to a range of non-standard computing scenarios. The framework also covers broader computing contexts, where there is no obvious human computer user. We define the critical notion of a ‘computational entity’, and show the role this plays in defining when computing is taking place in physical systems.

http://arxiv.org/abs/1309.7979

Chinese scientists examined 57 drinks – from herbal teas to fizzy drinks. Found that some helped to speed up the process where the body breaks down alcohol, helping relieve a hangover quicker. But some slowed the process down, meaning symptoms remained

Young people – and regular drinkers – produce more of the alcohol dehydrogenase enzyme, so they don’t feel the effects of alcohol as much as older people, said consultant hepatologist Dr Rajiv Jalan of University College Hospital London.The only good news is that, with age, hangover headaches become less of a problem.The headaches are the result of alcohol damaging the brain, causing it to swell temporarily and crash against the skull.But as we age our brains shrink, so there is more room for it to swell before it hits the bone.

via SPRITE found to be best cure for hangover | Mail Online.

University of Adelaide researchers have developed a process for turning waste plastic bags into a high-tech nanomaterial.
[…]
The process is also catalyst and solvent free, which means the plastic waste can be used without generating poisonous compounds.

via Turning plastic bags into high-tech materials.

In an advance that could dramatically shrink particle accelerators for science and medicine, researchers used a laser to accelerate electrons at a rate 10 times higher than conventional technology in a nanostructured glass chip smaller than a grain of rice.

via SLAC National Accelerator Laboratory – Researchers Demonstrate 'Accelerator on a Chip'.

http://www.feynmanlectures.info/docroot/I_toc.html