The visual processing of motion-defined transparency

Our understanding of how the visual system processes motion transparency, the phenomenon by which multiple directions of motion are perceived to co-exist in the same spatial region, has grown considerably in the past decade. There is compelling evidence that the process is driven by global-motion mechanisms. Consequently, although transparently moving surfaces are readily segmented over an extended space, the visual system cannot separate two motion signals that co-exist in the same local region. A related issue is whether the visual system can detect transparently moving surfaces simultaneously, or whether the component signals encounter a serial â??bottleneckâ?? during their processing? Our initial results show that, at sufficiently short stimulus durations, observers cannot accurately detect two superimposed directions; yet they have no difficulty in detecting one pattern direction in noise, supporting the serial-bottleneck scenario. However, in a second experiment, the difference in performance between the two tasks disappears when the component patterns are segregated. This discrepancy between the processing of transparent and non-overlapping patterns may be a consequence of suppressed activity of global-motion mechanisms when the transparent surfaces are presented in the same depth plane. To test this explanation, we repeated our initial experiment while separating the motion components in depth. The marked improvement in performance leads us to conclude that transparent motion signals are represented simultaneously.

The vulnerability of children with disabilities to abuse: a literature review.

The Children (N.I.) Order 1995 provides a legal framework for the care and protection of al! children including those with disabilities. The Order sets out a number of key principles which apply to all children, including that the child's welfare is paramount, that children should be safe and be protected through effective interventions, and that children with disabilities are to be recognised as children first.

Obesity in People with Learning Disabilities: the impact of nurse led health screenings and health promotion activities

Background. Obesity appears to be more common among people with intellectual disabilities, with few studies focusing on achieving weight reduction. Aim. Firstly, to follow up people identified as overweight and obese following special health screening clinics and to determine the actions taken. Secondly, to evaluate the impact of health promotion classes on participants' weight loss. Methods. A clinic led by two learning disbaility nurses was held for all people aged 10 years and over (n=464) who attended special services within the area of one Health and Social Services Trust in Northern Ireland. In a second study, the nurses organised health promotion classes for 20 people over a 6 - 8 week period. Findings. The health screen identified 64% of adults and 26% of 10 - 19 year olds as being overweight or obese. Moreover, those aged 40 - 49 years who were obese had significantly higher levels of blood pressure. However, information obtained from a follow up questionnaire sent after 3 months suggested that of the 122 people identified for wiehgt reduciton, action had been taken for only 34% of them and only three were reported to have lost weight. The health promotion classes, however, led to a significant reduction in weight and body mass index scores. Conclusion. Health screening per se has limited impact on reducing obesity levels in this client group. Rather, health personnel such as general practitioners, nurses and health promotion staff need to work in partnership with service staff, carers and people with intellectual disabiltieis to create more active lifestyles.

Changes in the attitudes of GPs to health screening of patients with learning disabilities

GP's appear reluctant to undertake health screening for people with learning disabilities. This article describes a specialist health screening service delivered mainly by community learning disability nurses to nearly 600 children and adults. Prior to the service being established, 141 GPs within a defined area were surveyed and 51% responded. Although a majority thought the service would be helpful, three-quarters felt it was better provided within the context of specialist services. After screening, 54% of the sample (318 persons) were referred to their GP for further assessment and treatment, nearly all for physoical health needs. A second study investigated the attitudes of 91 GPs who had patients refrrered. Those (45) who reported dealing with a referral were more favourably disposed to undertaking health screening within their practice, whereas those (23) who had been uninvolved continued to opt for specialist provision. Options for encouraging more GPs' to offer preventive health care to theisclient group are discussed, including medical training, extra consulting time and linking community learning disbaility nurses with GP practices.