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"Fitton, Laura"
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Mechanical adaptation of trabecular bone morphology in the mammalian mandible
Alveolar bone, together with the underlying trabecular bone, fulfils an important role in providing structural support against masticatory forces. Diseases such as osteoporosis or periodontitis cause alveolar bone resorption which weakens this structural support and is a major cause of tooth loss. However, the functional relationship between alveolar bone remodelling within the molar region and masticatory forces is not well understood. This study investigated this relationship by comparing mammalian species with different diets and functional loading (
Felis catus, Cercocebus atys, Homo sapiens, Sus scrofa, Oryctolagus cuniculus, Ovis aries
). We performed histomorphometric analyses of trabecular bone morphology (bone volume fraction, trabecular thickness and trabecular spacing) and quantified the variation of bone and tooth root volumes along the tooth row. A principal component analysis and non-parametric MANOVA showed statistically significant differences in trabecular bone morphology between species with contrasting functional loading, but these differences were not seen in sub-adult specimens. Our results support a strong, but complex link between masticatory function and trabecular bone morphology. Further understanding of a potential functional relationship could aid the diagnosis and treatment of mandibular diseases causing alveolar bone resorption, and guide the design and evaluation of dental implants.
Journal Article
Technological Analysis of the World’s Earliest Shamanic Costume: A Multi-Scalar, Experimental Study of a Red Deer Headdress from the Early Holocene Site of Star Carr, North Yorkshire, UK
Shamanic belief systems represent the first form of religious practice visible within the global archaeological record. Here we report on the earliest known evidence of shamanic costume: modified red deer crania headdresses from the Early Holocene site of Star Carr (c. 11 kya). More than 90% of the examples from prehistoric Europe come from this one site, establishing it as a place of outstanding shamanistic/cosmological significance. Our work, involving a programme of experimental replication, analysis of macroscopic traces, organic residue analysis and 3D image acquisition, metrology and visualisation, represents the first attempt to understand the manufacturing processes used to create these artefacts. The results produced were unexpected--rather than being carefully crafted objects, elements of their production can only be described as expedient.
Journal Article
The application of muscle wrapping to voxel-based finite element models of skeletal structures
Finite elements analysis (FEA) is now used routinely to interpret skeletal form in terms of function in both medical and biological applications. To produce accurate predictions from FEA models, it is essential that the loading due to muscle action is applied in a physiologically reasonable manner. However, it is common for muscle forces to be represented as simple force vectors applied at a few nodes on the model’s surface. It is certainly rare for any wrapping of the muscles to be considered, and yet wrapping not only alters the directions of muscle forces but also applies an additional compressive load from the muscle belly directly to the underlying bone surface. This paper presents a method of applying muscle wrapping to high-resolution voxel-based finite element (FE) models. Such voxel-based models have a number of advantages over standard (geometry-based) FE models, but the increased resolution with which the load can be distributed over a model’s surface is particularly advantageous, reflecting more closely how muscle fibre attachments are distributed. In this paper, the development, application and validation of a muscle wrapping method is illustrated using a simple cylinder. The algorithm: (1) calculates the shortest path over the surface of a bone given the points of origin and ultimate attachment of the muscle fibres; (2) fits a Non-Uniform Rational B-Spline (NURBS) curve from the shortest path and calculates its tangent, normal vectors and curvatures so that normal and tangential components of the muscle force can be calculated and applied along the fibre; and (3) automatically distributes the loads between adjacent fibres to cover the bone surface with a fully distributed muscle force, as is observed in vivo. Finally, we present a practical application of this approach to the wrapping of the temporalis muscle around the cranium of a macaque skull.
Journal Article
Virtual Functional Morphology: Novel Approaches to the Study of Craniofacial Form and Function
Recent developments in simulating musculoskeletal functioning in the craniofacial complex using multibody dynamic analysis and finite elements analysis enable comprehensive virtual investigations into musculoskeletal form and function. Because the growth of the craniofacial skeleton is strongly influenced by mechanical functioning, these methods have potential in investigating the normal and abnormal development of the skull: loading history during development can be predicted and bony adaptations to these loads simulated. Thus these methods can be used to predict the impact of altered loading or modifications of skull form early in ontogeny on the subsequent development of structures. Combining functional models with geometric morphometric methods (GMM), which are principally concerned with the study of variations of form, offers the opportunity to examine variations in form during development and the covariations between form and factors such as functional performance. Such a combination of functional models and GMM can potentially be applied in many useful ways, for example: to build and modify functional models, to assess the outcomes of remodelling studies by comparing the results with morphological changes during ontogeny, and to compare the outcomes of finite element analyses within a multivariate framework. Studies using these tools can not only investigate the development of the skull but also the mechanical processes and thus to some degree, behaviours underlying the development of variation among extant and fossil skeletal elements. By bringing together these tools from quite different comparative traditions, a novel and potentially powerful framework for simulation and statistical biomechanical analyses of form and function emerges. This paper reviews these recent developments in the context of the evolutionary and functional influences on skull development.
Journal Article
The form-function complex of the primate masticatory apparatus
Craniofacial morphology varies considerably between primate species with many aspects of structural variation occurring within the masticatory apparatus. These variations in masticatory fonn are frequently attributed to differences in diet however elucidating the relationship between masticatory form and function is complex. This study combines the techniques of shape analysis in a comparative study of the primate masticatory apparatus with three-dimensional biomechanical modelling of primate jaw mechanics. The relationship between masticatory form and function is investigated within a subfamily ofprimates, the Cercopithecinae. Species within this group display a range of masticatory forms, inhabit a wide range of environments, have varying diets and share close phylogenetic relationships making them an ideal group to investigate the relationship between structure and function. Using the techniques of geometric morphometrics a shape analysis was conducted in which variations within the masticatory forms of the Cercopithecinae were quantified. Functional predictions of observed shape differences were made and considered in light of known environmental and ecological factors with particular emphasis on dietary specialisations and fall back foods. The results of the shape analysis indicate that differences in body size, strata utilisation, and diet appear to play a major role in structuring adult morphological diversity within and among the Cercopithecinae. Many of the shape differences associated with an increased body size appear to reflect the selective pressures of increased predation risk, including increases in the length ofthe jaw and canine teeth. These morphological traits are associated with the production of a large gape and are hypothesised to be functional adaptations to the use of canines as weapons. Other major shape differences apparent between the Cercopithecinae were those associated with the proportion of leaves and fruit in the diet. The highly frugivorous Mandril/us species possessed features associated with increasing gape and retractile motions of the mandible ideal for incision of large fruits. By contrast the dietary specialist Theropithecus gelada possessed features associated with increasing the efficiency of food breakdown and muscle force production, necessary to process their more abrasive foodstuff (i.e. grasses).
Dissertation
Three Tips, Three Tools for Twitter
Twitter can seem daunting, but Twitter apps can actually help you run things more efficiently. My company oneforty is the Twitter app store and we have more than 3,000 applications in our directly. When you join Twitter, feel free to send us an @reply --we\"re @oneforty-- and we\"ll help answer any questions you have. Whatever you Tweet is put out there forever. Tweets can be deleted from the timeline on Twitter.com, but they cannot be actually erased; anything you Tweet will still be indexed on search engines and available on Twitter Search. As a professional, you are not only representing your personal brand, but you are also representing your company\"s or client\"s brand. Be conscious of what you say. Some people have actually lost their jobs over irresponsible Tweets. Most recently, CNN International fired senior editor Octavia Nasr for Tweeting that she was sad to hear that Ayatollah Mohammed Hussein Fadlallah, a Hezbollah leader, had died. With only 140 characters, it\"s easy to be misunderstood. Use your best judgement! I see a lot of people who think the path to influence on Twitter is through self-promotion. I see it\"s just the opposite: I think I got to 60,000 followers by making it about other people. My Twitter background isn\"t a picture of me; it\"s a promotion of charity:water. I wrote a book and created a business to help people learn about Twitter. I Tweeted about stuff I cared about, I was who I was, and now I\"m where I am today. I see many so-called \"social media gurus\" and some of the candidates in the MTV TJ contest literally asking for followers and making their whole Twitter presence very \"me, me, me.\" I highly encourage you to steer away from that for yourself and for your brand. Make it about your customers and make it about your friends. Eventually, Twitter will make those two one and the same.
Trade Publication Article
Embracing the Twitter ecosystem
It's the latest social-networking craze and users worldwide are \"tweeting\" to stay in touch. Here is an excerpt from Twitter for Dummies by Laura Fitton.; It's the latest social-networking craze and users worldwide are \"tweeting\" to stay in touch. Here is an excerpt from Twitter for Dummies by Laura Fitton.
Newspaper Article
Physical activity promoting teaching practices and children's physical activity within physical education lessons underpinned by motor learning theory (SAMPLE-PE)
Purpose: Movement competence is a key outcome for primary physical education (PE) curricula. As movement development in children emerges through physical activity (PA), it is important to determine the extent of PA promotion within movement competence focused teaching pedagogies. Therefore, this study aimed to assess children's moderate-to-vigorous PA (MVPA) and related teaching practices in primary PE within Linear pedagogy and Nonlinear pedagogy and to compare this to current practice within PE delivery in primary schools. Methods: Participants (n = 162, 53% females, 5-6y) were recruited from 9 primary schools within the SAMPLE-PE cluster randomised controlled trial. Schools were randomly-allocated to one of three conditions: Linear pedagogy, Nonlinear pedagogy, or control. Nonlinear and Linear pedagogy intervention schools received a PE curriculum delivered by trained deliverers over 15 weeks, while control schools followed usual practice. Children's MVPA was measured during 3 PE lessons (44 PE lessons in total) using an ActiGraph GT9X accelerometer worn on their non-dominant wrist. Differences between conditions for children's MVPA were analysed using multilevel model analysis. Negative binomial models were used to analyse teaching practices data. Results: No differences were found between Linear pedagogy, Nonlinear pedagogy and the control group for children's MVPA levels during PE. Linear and Nonlinear interventions generally included higher percentages of MVPA promoting teaching practices (e.g., Motor Content) and lower MVPA reducing teaching practices (e.g., Management), compared to the control group. Teaching practices observed in Linear and Nonlinear interventions were in line with the respective pedagogical principles. Conclusions: Linear and Nonlinear pedagogical approaches in PE do not negatively impact MVPA compared to usual practice. Nevertheless, practitioners may need to refine these pedagogical approaches to improve MVPA alongside movement competence. (Autor).
Journal Article
Effect of Linear and Nonlinear Pedagogy Physical Education Interventions on Children’s Physical Activity: A Cluster Randomized Controlled Trial (SAMPLE-PE)
Background: School-based interventions are a key opportunity to improve children’s physical activity (PA); however, there is lack of evidence about how pedagogical approaches to motor learning in physical education (PE) might affect PA in children. Therefore, this study aimed to assess how different pedagogical approaches in PE might affect children’s PA. Methods: Participants (n = 360, 5–6 years) from 12 primary schools within the SAMPLE-PE randomized controlled trial were randomly allocated to either Linear Pedagogy (LP: n = 3) or Nonlinear Pedagogy (NP: n = 3) interventions, where schools received a 15-week PE intervention delivered by trained coaches, or to a control group (n = 6), where schools followed usual practice. ActiGraph GT9X accelerometers were used to assess PA metrics (moderate-to-vigorous PA, mean raw acceleration and lowest acceleration over the most active hour and half hour) over whole and segmented weeks at baseline, immediately post-intervention and 6 months follow-up. Intention to treat analysis employing multilevel modelling was used to assess intervention effects. Results: LP and NP interventions did not significantly affect children’s PA levels compared to the control group. Conclusion: PE interventions based on LP and NP alone might not be effective in improving habitual PA in children.
Journal Article