Reflections on the concept of the central executive

Notes that the central executive lies at the heart of A. D. Baddeley's theory of working memory, but that what it does has been characterized in several different ways. This chapter reviews and brings together various interpretations of central executive functioning. The authors describe an experiment involving a novel cognitive task to point out the restrictive nature of the term 'executive capacity.' The chapter concludes by commenting briefly on the implications of a working memory model in which the executive does not play a major part.

Dietary modulation of the human colonic microbiota: updating the concept of prebiotics

Prebiotics are non-digestible (by the host) food ingredients that have a beneficial effect through their selective metabolism in the intestinal tract. Key to this is the specificity of microbial changes. The present paper reviews the concept in terms of three criteria: (a) resistance to gastric acidity, hydrolysis by mammalian enzymes and gastrointestinal absorption; (b) fermentation by intestinal microflora; (c) selective stimulation of the growth and/or activity of intestinal bacteria associated with health and wellbeing. The conclusion is that prebiotics that currently fulfil these three criteria are fructo-oligosaccharides, galacto-oligosaccharides and lactulose, although promise does exist with several other dietary carbohydrates. Given the range of food vehicles that may be fortified by prebiotics, their ability to confer positive microflora changes and the health aspects that may accrue, it is important that robust technologies to assay functionality are used. This would include a molecular-based approach to determine flora changes. The future use of prebiotics may allow species-level changes in the microbiota, an extrapolation into genera other than the bifidobacteria and lactobacilli, and allow preferential use in disease-prone areas of the body.

The eMinerals project: developing the concept of the virtual organisation to support collaborative work on molecular-scale environmental simulations

The eMinerals project has established an integrated compute and data minigrid infrastructure together with a set of collaborative tools,. The infrastructure is designed to support molecular simulation scientists working together as a virtual organisation aiming to understand a number of strategic processes in environmental science. The eMinerals virtual organisation is now working towards applying this infrastructure to tackle a new generation of scientific problems. This paper describes the achievements of the eMinerals virtual organisation to date, and describes ongoing applications of the virtual organisation infrastructure.

The concept of a new video detector for ghosted IF signals

The effect of terrestrial television multipath signals on the intermediate frequency (IF) vestigial sideband filter and the video detector are discussed. A new detector is proposed which, by processing the detected phase quadrature information, derives the correct phase for synchronous detection in the presence of multipath effects. This minimizes dispersion and produces a detected video signal with the linear addition of any ghosts.

The concept of exchangeability in ensemble forecasting

A set of random variables is exchangeable if its joint distribution function is invariant under permutation of the arguments. The concept of exchangeability is discussed, with a view towards potential application in evaluating ensemble forecasts. It is argued that the paradigm of ensembles being an independent draw from an underlying distribution function is probably too narrow; allowing ensemble members to be merely exchangeable might be a more versatile model. The question is discussed whether established methods of ensemble evaluation need alteration under this model, with reliability being given particular attention. It turns out that the standard methodology of rank histograms can still be applied. As a first application of the exchangeability concept, it is shown that the method of minimum spanning trees to evaluate the reliability of high dimensional ensembles is mathematically sound.

Are gay rights Islamophobic? A critique of some uses of the concept of homonationalism in activism and academia

The concept of ‘homonationalism’ refers to deployments of gay rights for racist and Islamophobic ends, resulting in the consolidation of more sexually inclusive, but racially exclusionary, ideas of citizenship. This article critiques some of the analyses that the concept has inspired in both activist and academic contexts. The critique concentrates on two texts, showing that they make inappropriate rhetorical moves and inaccurate or unsubstantiated claims, and that rather than unearthing structural undercurrents of racism from certain texts or events, they project such structures onto them. While the validity of ‘homonationalism’ as an analytical category is not disputed, some of its propounders assume its explanatory power to be greater than it appears to be. The implications of this critique for gay rights activism and reform are explored.