In vertebrate embryos, neural crest cells emerge from the dorsal neural tube and migrate along well defined pathways to form a wide diversity of tissues, including the majority of the peripheral nervous system (PNS). Members of the cadherin family of cell adhesion molecules play key roles during the initiation of migration, mediating the delamination of cells from the neural tube. However, a role for cadherins in the sorting and re-aggregation of the neural crest to form the PNS has not been established. We report the requirement for a protocadherin, chicken protocadherin-1 (Pcdh1), in neural crest cell sorting during the formation of the dorsal root ganglia (DRG). In embryos, cPcdh1 is highly expressed in the developing DRG, where it co-localizes with the undifferentiated and mitotically active cells along the perimeter. Pcdh1 can promote cell adhesion in vivo and disrupting Pcdh1 function in embryos results in fewer neural crest cells localizing to the DRG, with a concomitant increase in cells that migrate to the sympathetic ganglia. Furthermore, those cells that still localize to the DRG, when Pcdh1 is inhibited, are no longer found at the perimeter, but are instead dispersed throughout the DRG and are now more likely to differentiate along the sensory neuron pathway. These results demonstrate that Pcdh1-mediated cell adhesion plays an important role as neural crest cells coalesce to form the DRG, where it serves to sort cells to the mitotically active perimeter.
This paper describes a three year UK initiative—Applicability Study 1-to enhance the usability and credibility of detailed thermal simulation programs with particular reference. to the design of passive solar dwellings. Researchers at Leicester Polytechnic and the Building Research Establishment are working with ESP, HTB2 and SERIRES. The aims are to identify the problems for which these programs can be used reliably and those for which they cannot, to provide guidance on the best modelling techniques, indicate the uncertainty inherent in predictions, identify the attributes of programs which are necessary to obtain reliable results, and indicate areas in which additional theoretical or experimental research is needed. The results to date show that good agreement in some design trends can be obtained provided a high level of quality control is exercised and program users have a good understanding of the theoretical basis of the programs. There were, however, some situations in which the programs still predicted significant differences in the trends in energy consumption as the building design changed. These may be explained by the different algorithms employed by the detailed thermal simulation programs and errors in them.
This is the first of two papers focusing upon a new approach to staff development provision within Basildon and Thurrock Health Authority's service for people with learning disabilities. The ‘Education and Training for Change’ programme was set up in January 1990 on a contractual basis between the learning disabilities service (the purchaser) and a local HE College (the provider) which has since become a Polytechnic. Both the papers reflect on different aspects of the programme during its first eighteen months of operation, and attempt to draw some preliminary conclusions that may be of interest to other services.
This paper addresses the joint nature of the programme and the particular model of provision adopted, where the staff are ‘in, but not of the service’ i.e. sited in, but not employed or managed by the service. Some of the strengths and difficulties of such a model are highlighted, particularly as they apply during a time of organisational change, and the lessons we have drawn from our experiences are explored.
This article looks at the staff development strategy devised as part of the Education and Training for Change (ETCH) programme for Basildon & Thurrock Services for people with learning disabilities. The strategy covers all staff in the service, and takes account of the needs of staff facing possibly imminent hospital closure. The model of mutual support that underpins the strategy is described: it offers a positive view of change and an interpretation of hospital closure that has implications for both training provision and service management.
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