Fixed or variable noise in contrast discrimination? The jury's still out

The ability to distinguish one visual stimulus from another slightly different one depends on the variability of their internal representations. In a recent paper on human visual-contrast discrimination, Kontsevich et al (2002 Vision Research 42 1771 - 1784) re-considered the long-standing question whether the internal noise that limits discrimination is fixed (contrast-invariant) or variable (contrast-dependent). They tested discrimination performance for 3 cycles deg-1 gratings over a wide range of incremental contrast levels at three masking contrasts, and showed that a simple model with an expansive response function and response-dependent noise could fit the data very well. Their conclusion - that noise in visual-discrimination tasks increases markedly with contrast - has profound implications for our understanding and modelling of vision. Here, however, we re-analyse their data, and report that a standard gain-control model with a compressive response function and fixed additive noise can also fit the data remarkably well. Thus these experimental data do not allow us to decide between the two models. The question remains open. [Supported by EPSRC grant GR/S74515/01]

Ethnic groups as market segments: implications of the demand structure

Ethnic market potential in Britain has not yet been thoroughly researched. Important recent trends have focused mainly on the affective and emotional aspects of ethnicity, and included deliberations on the emergence of a revitalised neo-ethnic consciousness; its identification; politicisation, and the impact on it; of a rising third-world consciousness. This investigation attempts to take cognizance of the consuner demand of the ethnic Asian and West Indian groups, as specific market segments. It discusses the rationale for ethnic segmentation on the underlying premise, that the starting point for all product marketing is a response to perceived market opportunities. On the basis of this approach, the UK laundry detergent and automobile markets were investigated; as being representative of product categories constitutirg extremes along the purchase-search-time continuun in consuner decision-making. Ethnic groups were further analysed for their retail patronage patterns; media usage, and the differential effectiveness of alternative advertisirg strategies. The basic technique of marketing research namely the sample survey, was used with the aim of applying scientific techniques in obtaining information on ethnic groups. The integrated marketirg framework utilised allowed, moreover, for the collection of market research data on the specific issues of ethnic product penetration dealing with retailing, advertising and product promotion. The evidence highlights the fact that the cultural orientations of ethnic groups are instrunental in providing for differential demand structures. It points to the answer that ethnicity is an anchor not only for a deeper sense of identity; but also serves as a focus for the economic interests of ethnic groups. On this basis it is argued here, that since cultural levelling would eventually produce stagnation; current marketing strategies should utilise ethnic diversity as an econanic artifact; which; per se is necessary for profitability and growth; especially in innovative product design and development.

Interpreting adverse signals in diabetes drug development programs

Detection and interpretation of adverse signals during preclinical and clinical stages of drug development inform the benefit-risk assessment that determines suitability for use in real-world situations. This review considers some recent signals associated with diabetes therapies, illustrating the difficulties in ascribing causality and evaluating absolute risk, predictability, prevention, and containment. Individual clinical trials are necessarily restricted for patient selection, number, and duration; they can introduce allocation and ascertainment bias and they often rely on biomarkers to estimate long-term clinical outcomes. In diabetes, the risk perspective is inevitably confounded by emergent comorbid conditions and potential interactions that limit therapeutic choice, hence the need for new therapies and better use of existing therapies to address the consequences of protracted glucotoxicity. However, for some therapies, the adverse effects may take several years to emerge, and it is evident that faint initial signals under trial conditions cannot be expected to foretell all eventualities. Thus, as information and experience accumulate with time, it should be accepted that benefit-risk deliberations will be refined, and adjustments to prescribing indications may become appropriate. © 2013 by the American Diabetes Association.

Who gives a damn about intellectually disabled people and their families? Care-less spaces personified in the case of LB

On 5 October 2015 the inquest into Connor Sparrowhawk’s death began. A young autistic man, aged 18, died in the bath on 4 July 2013. He had a seizure. The rolling tweets from @LBInquest are harrowing to say the least. Unimaginable torture for Sara and Richard (his mother and step-father), as well as his siblings and others caring. Comments from the inquest such as ‘I felt that Connor should be checked on every 5 or 10 minutes when he was in the bath because of his epilepsy’ and ‘ensuring someone was outside the door when he was bathing was basic nursing care’ sound all the alarm bells for lack of care, because allegedly this did not happen. Clearly there was no one person looking out for him when he needed it the most. On 16 October 2015 the inquest jury found Connor’s death was contributed by neglect. This article will explore the absence of care in a care-less system.