Towards an integrated experimental-theoretical approach for assessing the mechanistic basis of hair and feather morphogenesis.

In his seminal 1952 paper, 'The Chemical Basis of Morphogenesis', Alan Turing lays down a milestone in the application of theoretical approaches to understand complex biological processes. His deceptively simple demonstration that a system of reacting and diffusing chemicals could, under certain conditions, generate spatial patterning out of homogeneity provided an elegant solution to the problem of how one of nature's most intricate events occurs: the emergence of structure and form in the developing embryo. The molecular revolution that has taken place during the six decades following this landmark publication has now placed this generation of theoreticians and biologists in an excellent position to rigorously test the theory and, encouragingly, a number of systems have emerged that appear to conform to some of Turing's fundamental ideas. In this paper, we describe the history and more recent integration between experiment and theory in one of the key models for understanding pattern formation: the emergence of feathers and hair in the skins of birds and mammals.

Psychosocial work factors, physical work load and associated musculoskeletal symptoms among home care workers.

This study was based on a questionnaire and included a group of home care workers (HCW) (n = 305) and a reference group of municipal employees (n = 694). The relationship between the work environment and musculoskeletal symptoms was analysed. The HCW were less satisfied with their control over their work and stimulus from their work and had a higher physical work load and prevalence of musculoskeletal symptoms, compared with the reference group. The Rate Ratio (RR) of neck and shoulder symptoms among HCW was 83 and 54%, respectively, higher among those reporting a "high" psychological work load compared with those reporting a "low" load. The highest RR for a single risk indicator was 2.5, and this concerned low-back symptoms among HCW who often worked with twisted postures. A combination of "poor" psychosocial work environment and "high" physical work load produced the highest RR for work-related neck (RR = 2.57) and shoulder (RR = 2.13) symptoms.

Risk indicators in the psychosocial and physical work environment for work-related neck, shoulder and low back symptoms: a study among blue- and white-collar workers in eight companies.

The study was based on a questionnaire and included 209 white-collar workers and 241 blue-collar workers in eight companies. The questionnaire deals with musculoskeletal symptoms, psychosocial and physical load factors. The relationship between job factors and neck, shoulder and low-back symptoms was analysed. The Nordic Musculoskeletal Questionnaire (NMQ) was supplemented with an additional question regarding whether or not the symptoms were believed to be related to work. The associations between the psychosocial factors and musculoskeletal symptoms were substantially higher when solely work-related symptoms were included in the analyses; these associations were of the same magnitude as that between several physical work load factors and work-related musculoskeletal symptoms. This study suggests that calculations of associations based solely on the NMQ, without the inclusion of questions to elicit reports of symptoms that are believed to be work-related, could have a powerful effect-masking consequence.

Work-related and non-work-related musculoskeletal symptoms.

The purpose of the study was to analyse the prevalence of self-reported work-related and non-work-related musculoskeletal symptoms among white- and blue-collar workers. The study was carried out at eight metal industry companies and included 450 subjects, where 241 were blue-collar workers and 209 were white-collar workers. Among the blue-collar workers 39% were females and among the white-collar workers 35% were females. The study was based on a questionnaire, using the general standardized Nordic Musculoskeletal Questionnaire (NMQ). The NMQ was completed with a question concerning whether or not the symptoms were believed to be related to the individual's present work. It was found that the differences between white- and blue-collar workers' musculoskeletal symptoms became greater when solely work-related symptoms were included, compared with symptoms in general according to the NMQ. Furthermore, it was found in both groups that the prevalence of musculoskeletal symptoms decreased substantially when solely work-related symptoms were included, compared with symptoms in general.