Sinus and meningeal vessel pattern changes induced by artificial cranial deformation: A pilot study

This study explores the changes in sinus and meningeal vessel patterns caused by various types of artificial cranial deformation. Endocranial casts were prepared from six crania exhibiting one of three types of deformation (lambdoid, parallelo-fronto-occipital and fronto-vertico-occipital), as well as from 15 undeformed crania. Vessel and sulcus patterns of each cranium were analysed and these patterns included depth of impressions, size and number of vessels, and directional pathways of vessels. Comparisons were made within and between the different deformation types. The results indicated that deformation has an effect upon the pattern, shape and depth of vessel impressions. Vessels tended to be flattened in the areas directly affected by cranial deformation, and there was often compensatory enlargement of other vessels. Further, three of the six artificially deformed crania exhibited enlarged occipital/marginal sinuses, suggesting that this trait is developmentally plastic and greatly influenced by environmental factors.     

Daily rates of dentine formation in macaque tooth roots

When tetracycline antibiotics are administered either orally or by injection they bind at the forming mineral front of the dentine and become incorporated into teeth as a permanent label. In this study, oxytetracycline was used as a label in order to investigate the growth of root dentine in macaques. There are no good data available in the literature for daily rates of root dentine formation over a prolonged period of time in either humans or macaques. Records of ten doses of oxytetracycline administered orally at irregular intervals (but at the same time of day) over a period of 10 months to a young rhesus macaque monkey (Macaca mulatta) were used to calculate the rate of dentine formation in tooth roots. Rates of dentine formation in the first portion of third permanent molar root formation, and in the apical portion of permanent canine and premolar root formation, were consistently between 3 μm and 4 μm per day. There was no evidence in this study of a gradual decrease in daily dentine formation rate from the crown to the root, or along the length of a dentine tubule through the bulk of the dentine, as has been implied previously. With the exception of faster rates recorded in cusps or slower rates recorded at the very beginning or very end of primary dentine secretion in other studies, the results of the present study suggest a consistent rate of dentine formation in permanent macaque teeth. What data there are for human dentine formation rates suggests that it is likely this finding can be extended to human dentine as well.     

A SPATIAL ANALYSIS OF SECTORAL VARIATIONS IN RETURNS TO EXTERNAL SCALE

ABSTRACT.  This paper reports results of spatially explicit analyses of external scale effects across a variety of sectors, including manufacturing. Using data from New England counties, earnings are found to exhibit increasing returns to urbanization in every sector. Returns to sectoral localization are mixed, however, with increasing returns in one sector, constant returns in five sectors, and decreasing returns in two sectors. External scale effects are fairly confined in their spatial extent, with only retailing and services particularly marked by spillover effects from neighboring counties.     

Understanding local innovation systems in peripheral tourism destinations

Tourism destinations in peripheral areas are often large regions established by centralised government agencies to encourage collaboration between dispersed communities and foster innovation. Relatively little research attention has been paid to the impact that centrally defined destination boundaries have on whether and how small communities contribute to innovation at a regional level. This paper examines the case of Burra, a small town in rural South Australia. It analyses the networking, collaboration and knowledge exchange behaviour of tourism stakeholders in the context of the state-government-defined ‘Clare Valley’ tourism region. Data were drawn from a web-based social network analysis, in-depth interviews, historic document analysis and field observations. The study found that the local tourism system had limited aspirations and capabilities to collaborate with other towns in the region. Lack of regional engagement was only partially due to intra-regional competition and resistance to regional boundaries. More significant barriers included a local culture of operating in isolation, an embedded reliance on public sector leadership to manage systemic interactions, an aging system with limited ambition to change and an inability to harness in-migrants and externally based stakeholders to stimulate knowledge transfer. Changing the imposed destination boundaries would have limited impact on the operation of the local system. The paper concludes that effective regional destination development in peripheral areas needs to be better informed by more detailed understandings of local tourism systems and their capacities to engage.