Preanalytical processing of archaeological mammal enamel apatite carbonates for stable isotope investigations: a comparative analysis of the effect of acid treatment on samples from Northwest Australia

Stable isotopic analysis of palaeontological and archaeological biogenic apatite carbonates from herbivorous mammalian species represents an important tool for worldwide palaeoecological research. Tooth enamel carbonates are more resistant to taphonomic processes than bone or dentine carbonates but are not invulnerable to diagenesis. As such, they require careful preanalytical processing that considers depositional environment and age. An established part of this process includes a weak acid treatment to remove soluble exogenous carbonates; however, published treatment times for isotopic studies of archaeological tooth enamel are variable and range from 15\ua0min to over 8\ua0hr. This study tests three different pretreatment protocols on modern and Pleistocene age archaeological kangaroo teeth (dating from contemporary to 46,000 bp) to assess the effect of acid treatment time on isotopic integrity. The results indicate that treatment time is a critical parameter for producing consistency across results and shorter pretreatments of 4\ua0hr or less are preferable for removing diagenetic carbonates while minimising alteration of the biological signal

A comparison of two methods of quantifying masticatory pressures developed under dentures with variable occlusal widths

Pressures developed during mastication with removable dental prostheses have beer quantified by two methods. This pilot study (1) compares the peak pressure method of pressure quantification with the integrated curve method of quantification and (2) continues the exploration of the effect of the width of the occlusal table on pressures developed under dentures. A set of specially designed experimental dentures was constructed for one individual. The mandibular experimental denture contained a series of pressure transducers by which masticatory pressures were recorded. These pressures were monitored between the denture base and the residual ridge tissues. Several interchangeable posterior occlusal segments, varying only in the width of the occlusal table, were fabricated for the opposing maxillary denture. Masticatory pressure and total ridge pressure were quantified by the integrated curve method and the peak pressure method. Both methods indicated a direct relationship between masticatory pressures produced and the width of the occlusal table. A similar direct relationship between total ridge pressure and occlusal width was suggested statistically by the integrated curve method, and graphically by both methods.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73368/1/j.1365-2842.1979.tb00407.x.pd

Dentifrices, mouthwashes, and remineralization/caries arrestment strategies

While our knowledge of the dental caries process and its prevention has greatly advanced over the past fifty years, it is fair to state that the management of this disease at the level of the individual patient remains largely empirical. Recommendations for fluoride use by patients at different levels of caries risk are mainly based on the adage that more is better. There is a general understanding that the fluoride compound, concentration, frequency of use, duration of exposure, and method of delivery can influence fluoride efficacy. Two important factors are (1) the initial interaction of relatively high concentrations of fluoride with the tooth surface and plaque during application and (2) the retention of fluoride in oral fluids after application

Secondary school students' understanding of the socio-emotional nature of the New Zealand Key Competencies

In its 2007 curriculum, New Zealand introduced Key Competencies (KCs) that are intended to ensure students’ future participation in the economy, communities, and also to introduce metacognitive and socio-emotional dimensions to learning. The KCs also have important implications for contributing to students’ wellbeing and resilience. However, they are open to interpretation and have been conceptualised, implemented, and taught in different ways. This research explored students’ views of the KCs. Twelve students from five secondary schools were interviewed to explore their understanding and value of the KCs and their ideas for teaching them. Thematic analysis was used to analyse the data. Results show that participants value the KCs and interpreted them in a variety of ways, though they often failed to discuss the interconnection between the KCs or identify socio-emotional aspects of the KCs. Implications for teaching the KCs in school are discussed

Secondary school students' understanding of the socio-emotional nature of the New Zealand Key Competencies

In its 2007 curriculum, New Zealand introduced Key Competencies (KCs) that are intended to ensure students’ future participation in the economy, communities, and also to introduce metacognitive and socio-emotional dimensions to learning. The KCs also have important implications for contributing to students’ wellbeing and resilience. However, they are open to interpretation and have been conceptualised, implemented, and taught in different ways. This research explored students’ views of the KCs. Twelve students from five secondary schools were interviewed to explore their understanding and value of the KCs and their ideas for teaching them. Thematic analysis was used to analyse the data. Results show that participants value the KCs and interpreted them in a variety of ways, though they often failed to discuss the interconnection between the KCs or identify socio-emotional aspects of the KCs. Implications for teaching the KCs in school are discussed