Patient-specific computational biomechanics for simulating adolescent scoliosis surgery : predicted vs clinical correction for a preliminary series of six patients

Scoliosis is a spinal deformity that requires surgical correction in progressive cases. In order to optimize surgical outcomes, patient-specific finite element models are being developed by our group. In this paper, a single rod anterior correction procedure is simulated for a group of six scoliosis patients. For each patient, personalised model geometry was derived from low-dose CT scans, and clinically measured intra-operative corrective forces were applied. However, tissue material properties were not patient-specific, being derived from existing literature. Clinically, the patient group had a mean initial Cobb angle of 47.3 degrees, which was corrected to 17.5 degrees after surgery. The mean simulated post-operative Cobb angle for the group was 18.1 degrees. Although this represents good agreement between clinical and simulated corrections, the discrepancy between clinical and simulated Cobb angle for individual patients varied between -10.3 and +8.6 degrees, with only three of the six patients matching the clinical result to within accepted Cobb measurement error of +-5 degrees. The results of this study suggest that spinal tissue material properties play an important role in governing the correction obtained during surgery, and that patient-specific modelling approaches must address the question of how to prescribe patient-specific soft tissue properties for spine surgery simulation.

Exposure of pipe insulation to high temperatures from domestic pumped storage (split) solar water heating systems in Australia and New Zealand

Pipe insulation between the collector and storage tank on pumped storage (commonly called split), solar water heaters can be subject to high temperatures, with a maximum equal to the collector stagnation temperature. The frequency of occurrence of these temperatures is dependent on many factors including climate, hot water demand, system size and efficiency. This paper outlines the findings of a computer modelling study to quantify the frequency of occurrence of pipe temperatures of 80 degrees Celsius or greater at the outlet of the collectors for these systems. This study will help insulation suppliers determine the suitability of their materials for this application. The TRNSYS program was used to model the performance of a common size of domestic split solar system, using both flat plate and evacuated tube, selective surface collectors. Each system was modelled at a representative city in each of the 6 climate zones for Australia and New Zealand, according to AS/NZS4234 - Heat Water Systems - Calculation of energy consumption, and the ORER RECs calculation method. TRNSYS was used to predict the frequency of occurrence of the temperatures that the pipe insulation would be exposed to over an average year, for hot water consumption patterns specified in AS/NZS4234, and for worst case conditions in each of the climate zones. The results show; * For selectively surfaced, flat plate collectors in the hottest location (Alice Sprints) with a medium size hot water demand according to AS/NZS2434, the annual frequency of occurrence of temperatures at and above 80 degrees Celsius was 33 hours. The frequency of temperatures at and above 140 degrees Celsius was insignificant. * For evacuated tube collectors in the hottest location (Alice Springs), the annual frequency of temperatures at and above 80 degrees Celsius was 50 hours. Temperatures at and above 140 degrees Celsius were significant and were estimated to occur for more than 21 hours per year in this climate zone. Even in Melbourne, temperatures at and above 80 degrees can occur for 12 hours per year and at and above 140 degrees for 5 hours per year. * The worst case identified was for evacuated tube collectors in Alice Springs, with mostly afternoon loads in January. Under these conditions, the frequency of temperatures at and above 80 degrees Celsius was 10 hours for this month only. Temperatures at and above 140 degrees Celsius were predicted to occur for 5 hours in January.

Validation and automation of the DYNJAWS component module of the BEAMnrc Monte Carlo code

The purpose of this work is to validate and automate the use of DYNJAWS; a new component module (CM) in the BEAMnrc Monte Carlo (MC) user code. The DYNJAWS CM simulates dynamic wedges and can be used in three modes; dynamic, step-and-shoot and static. The step-and-shoot and dynamic modes require an additional input file defining the positions of the jaw that constitutes the dynamic wedge, at regular intervals during its motion. A method for automating the generation of the input file is presented which will allow for the more efficient use of the DYNJAWS CM. Wedged profiles have been measured and simulated for 6 and 10 MV photons at three field sizes (5 cm x 5 cm , 10 cm x10 cm and 20 cm x 20 cm), four wedge angles (15, 30, 45 and 60 degrees), at dmax and at 10 cm depth. Results of this study show agreement between the measured and the MC profiles to within 3% of absolute dose or 3 mm distance to agreement for all wedge angles at both energies and depths. The gamma analysis suggests that dynamic mode is more accurate than the step-and-shoot mode. The DYNJAWS CM is an important addition to the BEAMnrc code and will enable the MC verification of patient treatments involving dynamic wedges.

Pressure, oxygen tension and temperature in the periosteal callus during bone healing - An in vivo study in sheep

Adequate blood supply and sufficient mechanical stability are necessary for timely fracture healing. Damage to vessels impairs blood supply; hindering the transport of oxygen which is an essential metabolite for cells involved in repair. The degree of mechanical stability determines the mechanical conditions in the healing tissues. The mechanical conditions can influence tissue differentiation and may also inhibit revascularization. Knowledge of the actual conditions in a healing fracture in vivo is extremely limited. This study aimed to quantify the pressure, oxygen tension and temperature in the external callus during the early phase of bone healing. Six Merino-mix sheep underwent a tibial osteotomy. The tibia was stabilized with a standard mono-lateral external fixator. A multi-parameter catheter was placed adjacent to the osteotomy gap on the medial aspect of the tibia. Measurements of oxygen tension and temperature were performed for ten days post-op. Measurements of pressure were performed during gait on days three and seven. The ground reaction force and the interfragmentary movements were measured simultaneously. The maximum pressure during gait increased (p=0.028) from three (41.3 [29.2-44.1] mm Hg) to seven days (71.8 [61.8-84.8] mm Hg). During the same interval, there was no change (p=0.92) in the peak ground reaction force or in the interfragmentary movement (compression: p=0.59 and axial rotation: p=0.11). Oxygen tension in the haematoma (74.1 mm Hg [68.6-78.5]) was initially high post-op and decreased steadily over the first five days. The temperature increased over the first four days before reaching a plateau at approximately 38.5 degrees C on day four. This study is the first to report pressure, oxygen tension and temperature in the early callus tissues. The magnitude of pressure increased even though weight bearing and IFM remained unchanged. Oxygen tensions were initially high in the haematoma and fell gradually with a low oxygen environment first established after four to five days. This study illustrates that in bone healing the local environment for cells may not be considered constant with regard to oxygen tension, pressure and temperature.

English language study abroad program : an investigation of Hong Kong pre-service teachers’ experiences of a language immersion program

There has been minimal research focused on short-term study abroad language immersion programs, in particular, with home-stay families. The importance of authentic intercultural experience is increasingly clear and was acknowledged as central to the process of language learning (Liddicoat, 2004). In Hong Kong, education programs for pre-service language teachers have significantly emphasised language and intercultural training through short-term study abroad, and these short overseas language immersion courses have become a compulsory component for teacher training (Bodycott & Crew, 2001) in the last decade. This study aims to investigate eight Hong Kong pre-service teachers’ and their home-stay families’ experiences of a short-term (two months) language immersion program in Australia. The focus is on listening to commentaries concerning the development of communicative competence, intercultural competence and professional growth during the out-of-class study abroad experience. The conceptual framework adopted in this study views language and intercultural learning from social constructivist perspectives. Central to this framing is the notion that the internalisation of higher mental functions involves the transfer from the inter-psychological to the intra-psychological plane, that is, a progression process from the socially supported to individually controlled performance. From this perspective, language serves as a way to communicate about, and in relation to, actions and experience. Three research questions were addressed and studied through qualitative methodology. 1. How do the pre-service teachers and their home-stay families perceive the out-of-class component of the program in terms of opportunities for the development of language proficiency and communicative competence? 2. How do the pre-service teachers and their home-stay families perceive the out-of-class component of the program in terms of the development of intercultural competence? 3. How do the pre-service teachers and home-stay families perceive the outof- class component of the program in terms of teachers’ professional growth? Data were generated from multiple data collection methods and analysed through thematic analysis from both a “bottom up” and “top down” approach. The study showed that the pre-service teachers perceived that the immersion program influenced, to varying degrees, their language proficiency, communication and intercultural awareness, as well as their self-awareness and professional growth. These pre-service teachers believed that effective language learning centres on active engagement in the target language community. A mismatch between the views and evaluations of the two groups – the pre-service teachers and the home-stay family members – provides some evidence of misalignments in terms of expectations and perceptions of each other’s roles and responsibilities. The study has highlighted challenges encountered, and provided suggestions for ways of meeting these challenges. The inclusion in the study of the home-stay families’ perceptions and commentaries provided insights, which can inform program development. There is clearly further work to be done in terms of predeparture orientation and preparation, not only for the main participants themselves, the students, but also for the host families.

Mentoring across the professions : some issues and challenges

Mentoring has been identified as a valuable learning activity for beginners and more experienced personnel across a range of professions. For example, education, nursing, medicine, law, accounting , and public administration are among those professions that have utilised mentoring programs as a way of socialising and developing the skills and competencies of new professionals. The definition of mentoring used in this paper comes from Hansford, Tennent, and Ehrich (2002, 2003) that describes mentoring as a process whereby a more experienced practitioner works with, supports, guides and provides professional development to a less experienced practitioner. Mentoring, then, is often used to develop novice or less experienced professionals at two important phases in their career: (i) during their initial university training; and (ii) after graduation from university. For example, within the field experience components of many university degrees in education, nursing, medicine, social work, and other human service programs, students are assigned workplace mentors who assist them in transferring important skills and knowledge learned at university into practical setting. For concentrated periods of time during their degree, pre-service teachers, pre-service nurses and medical students work in the field alongside a workplace mentor.

Spatial population genetic structure reveals strong natal site fidelity in Echinocladius martini (Diptera: Chironomidae) in northeast Queensland, Australia

1. A diverse array of patterns has been reported regarding the spatial extent of population genetic structure and effective dispersal in freshwater macroinvertebrates. In river systems, the movements of many taxa can be restricted to varying degrees by the natural stream channel hierarchy. 2. In this study, we sampled populations of the non-biting freshwater midge Echinocladius martini in the Paluma bioregion of tropical northeast Queensland to investigate fine scale patterns of within- and among-stream dispersal and gene flow within a purported historical refuge. We amplified a 639 bp fragment of mitochondrial COI and analysed genetic structure using pairwise ΦST, hierarchical AMOVA, Mantel tests and a parsimony network. Genetic variation was partitioned among stream sections using Streamtree to investigate the effect of potential instream dispersal barriers. 3. The data revealed strong natal site fidelity and significant differentiation among neighbouring, geographically proximate streams. We found evidence for only episodic adult flight among sites on separate stream reaches. Overall, however, our data suggested that both larval and adult dispersal was largely limited to within a stream channel. 4. This may arise from a combination of the high density of riparian vegetation physically restricting dispersal and from the joint effects of habitat stability and large population sizes. Together these may mitigate the requirement for movement among streams to avoid inbreeding and local extinction due to habitat change and may thus enable persistence of upstream populations in the absence of regular compensatory upstream flight. Taken together, these data suggest that dispersal of E. martini is highly restricted, to the scale of only a few kilometres, and hence occurs predominantly within the natal stream.

Coursework masters students' perspectives on career development learning

Coursework Masters’ students have been identified as a ‘forgotten’ cohort by the Queensland University of Technology (QUT) Careers and Employment (C&E) Service. Traditionally, these students have been included in undergraduate career development activities. However, coursework Masters’ students are arguably a specialised cohort due to the advanced learning implicit in many of their degrees. A brief survey was designed to better understand how to assist QUT coursework Masters students with career development activities. Students were emailed an invitation to complete a brief online survey asking for their assistance in planning appropriate career development activities for their cohort. Questions included reasons for undertaking a Masters degree and preferred topics and times for career development activities. 615 students completed the survey. This brief report will report the results of the survey and highlight suggestions for career development practitioners and services

'Being-in-the-world-of-care' : the lived experiences of older people receiving community aged care packages in Queensland

It has been recognised in current literature that, in general, Australia’s population is ageing and that older people are increasingly choosing to continue to live in the community in their own homes for as long as possible. Such factors of social change are expected to lead to larger numbers of older people requiring community care services for longer periods. Despite this, there is little information available in the literature on the perceptions and experiences of older people regarding community-based care and support. This study explores the lived experience of a small group of older people living in South East Queensland who were receiving a level of care consistent with the Community Aged Care Package (CACP). It also sought to examine the impact and meaning of that care on the older person’s overall lifestyle, autonomy, and personal satisfaction. In-depth interviews were undertaken with these older people, and were analysed using Heidegger’s interpretive hermeneutical phenomenological approach. Shared narratives were then explored using Ricoeur’s narrative analysis framework. In order to sensitise the researcher to the unconscious or symbolic aspects of the care experience, Wolfensberger’s social role valorization theory (SRV) was also utilised during a third phase of analysis. Methodological rigour was strengthened within this study through the use of reflexivity and an in-depth member check discussion that was conducted with each participant. The interviews revealed there were significant differences in expectations, understanding, and perceptions between older people and their carers or service providers. The older person perceived care primarily in relational terms, and clearly preferred active participation in their care and a consistent relationship with a primary carer. Older people also sought to maintain their sense of autonomy, lifestyle, home environment, routines, and relationships, as closely as possible to those that existed prior to their requiring assistance. However, these expectations were not always supported by the care model. On the whole, service providers did not always understand what older people perceived was important within the care context. Carers seldom looked beyond the provision of assistance with specific daily tasks to consider the real impact of care on the older person. The study identified that older people reported a range of experiences when receiving care in their own homes. While some developed healthy and supportive connections with their carers, others experienced ageism, abuse, and exploitation. Unsatisfactory interactions at times resulted in a loss, to varying degrees, of their independence, their possessions, and their connectedness with others. There is therefore a need for service providers to pay more attention to the perceptions and self-perceived needs of older people, to avoid unintended or unnecessary negative impacts occurring within care provision. The study provides valuable information regarding the older person’s experience that will assist in supporting the further development and improvement of this model of care. It is proposed that these insights will enable CACPs to cater more closely to the actual needs and preferences of older people, and to avoid causing preventable harm to care recipients.

Generalized binomial Tau-leap method for biochemical kinetics incorporating both delay and intrinsic noise

The delay stochastic simulation algorithm (DSSA) by Barrio et al. [Plos Comput. Biol.2, 117–E (2006)] was developed to simulate delayed processes in cell biology in the presence of intrinsic noise, that is, when there are small-to-moderate numbers of certain key molecules present in a chemical reaction system. These delayed processes can faithfully represent complex interactions and mechanisms that imply a number of spatiotemporal processes often not explicitly modeled such as transcription and translation, basic in the modeling of cell signaling pathways. However, for systems with widely varying reaction rate constants or large numbers of molecules, the simulation time steps of both the stochastic simulation algorithm (SSA) and the DSSA can become very small causing considerable computational overheads. In order to overcome the limit of small step sizes, various τ-leap strategies have been suggested for improving computational performance of the SSA. In this paper, we present a binomial τ- DSSA method that extends the τ-leap idea to the delay setting and avoids drawing insufficient numbers of reactions, a common shortcoming of existing binomial τ-leap methods that becomes evident when dealing with complex chemical interactions. The resulting inaccuracies are most evident in the delayed case, even when considering reaction products as potential reactants within the same time step in which they are produced. Moreover, we extend the framework to account for multicellular systems with different degrees of intercellular communication. We apply these ideas to two important genetic regulatory models, namely, the hes1 gene, implicated as a molecular clock, and a Her1/Her 7 model for coupled oscillating cells.

Asphalt concrete surfaces macrotexture determination from still images

Road surface macrotexture is identified as one of the factors contributing to the surface's skid resistance. Existing methods of quantifying the surface macrotexture, such as the sand patch test and the laser profilometer test, are either expensive or intrusive, requiring traffic control. High-resolution cameras have made it possible to acquire good quality images from roads for the automated analysis of texture depth. In this paper, a granulometric method based on image processing is proposed to estimate road surface texture coarseness distribution from their edge profiles. More than 1300 images were acquired from two different sites, extending to a total of 2.96 km. The images were acquired using camera orientations of 60 and 90 degrees. The road surface is modeled as a texture of particles, and the size distribution of these particles is obtained from chord lengths across edge boundaries. The mean size from each distribution is compared with the sensor measured texture depth obtained using a laser profilometer. By tuning the edge detector parameters, a coefficient of determination of up to R2 = 0.94 between the proposed method and the laser profilometer method was obtained. The high correlation is also confirmed by robust calibration parameters that enable the method to be used for unseen data after the method has been calibrated over road surface data with similar surface characteristics and under similar imaging conditions.

Labyrinthine literacies : navigating cultural agency in the arrival and requiem for a beast

The OED reminds us as surely as Ovid that a labyrinth is a “structure consisting of a number of intercommunicating passages arranged in bewildering complexity, through which it is it difficult or impossible to find one’s way without guidance”. Both Shaun Tan’s The Arrival (2006) and Matt Ottley’s Requiem for a Beast: A Work for Image, Word and Music (2007) mark a kind of labyrinthine watershed in Australian children’s literature. Deploying complex, intercommunicating logics of story and literacy, these books make high demands of their reader but also offer guidance for the successful navigation of their stories; for their protagonists as surely as for readers. That the shared logic of navigation in each book is literacy as privileged form of meaning-making is not surprising in the sense that within “a culture deeply invested in myths of individualism and self-sufficiency, it is easy to see why literacy is glorified as an attribute of individual control and achievement” (Williams and Zenger 166). The extent to which these books might be read as exemplifying desired norms of contemporary Australian culture seems to be affirmed by the fact of Tan and Ottley winning the Australian “Picture Book of the Year” prize awarded by the Children’s Book Council of Australia in 2007 and 2008 respectively. However, taking its cue from Ottley’s explicit intertextual use of the myth of Theseus and from Tan’s visual rhetoric of lostness and displacement, this paper reads these texts’ engagement with tropes of “literacy” in order to consider the ways in which norms of gender and culture seemingly circulated within these texts might be undermined by constructions of “nation” itself as a labyrinth that can only partly be negotiated by a literate subject. In doing so, I argue that these picture books, to varying degrees, reveal a perpetuation of the “literacy myth” (Graff 12) as a discourse of safety and agency but simultaneously bear traces of Ariadne’s story, wherein literacy alone is insufficient for safe navigation of the labyrinth of culture.

Designing university, government and industry community engagement to build informed and effective interventions in the area of road safety

Individuals, community organisations and industry have always been involved to varying degrees in efforts to address the Queensland road toll. Traditionally, road crash prevention efforts have been led by state and local government organisations. While community and industry groups have sometimes become involved (e.g. Driver Reviver campaign), their efforts have largely been uncoordinated and under-resourced. A common strength of these initiatives lies in the energy, enthusiasm and persistence of community-based efforts. Conversely, a weakness has sometimes been the lack of knowledge, awareness or prioritisation of evidence-based interventions or their capacity to build on collaborative efforts. In 2000, the Queensland University of Technology’s Centre for Accident Research and Road Safety – Queensland (CARRS-Q) identified this issue as an opportunity to bridge practice and research and began acknowledging a selection of these initiatives, in partnership with the RACQ, through the Queensland Road Safety Awards program. After nine years it became apparent there was need to strengthen this connection, with the Centre establishing a Community Engagement Workshop in 2009 as part of the overall Awards program. With an aim of providing community participants opportunities to see, hear and discuss the experiences of others, this event was further developed in 2010, and with the collaboration of the Queensland Department of Transport and Main Roads, the RACQ, Queensland Police Service and Leighton Contractors Pty Ltd, a stand-alone Queensland Road Safety Awards Community Engagement Workshop was held in 2010. Each collaborating organisation recognised a need to mobilise the community through effective information and knowledge sharing, and recognised that learning and discussion can influence lasting behaviour change and action in this often emotive, yet not always evidence-based, area. This free event featured a number of speakers representing successful projects from around Australia and overseas. Attendees were encouraged to interact with the speakers, to ask questions, and most importantly, build connections with other attendees to build a ‘community road safety army’ all working throughout Australia on projects underpinned by evaluated research. The workshop facilitated the integration of research, policy and grass-roots action enhancing the success of community road safety initiatives. For collaboration partners, the event enabled them to transfer their knowledge in an engaged approach, working within a more personal communication process. An analysis of the success factors for this event identified openness to community groups and individuals, relevance of content to local initiatives, generous support with the provision of online materials and ongoing communication with key staff members as critical and supports the view that the university can directly provide both the leadership and the research needed for effective and credible community-based initiatives to address injury and death on the roads.

Numerical exploration of the defect’s effect on mechanical properties of nanowires under torsion

Molecular dynamics (MD) simulations have been carried out to investigate the defect’s effect on the mechanical properties of single-crystal copper nanowire with different surface defects, under torsion deformation. The torsional rigidity is found insensitive to the surface defects and the critical angle appears an obvious decrease due to the surface defects, the largest decrease is found for the nanowire with surface horizon defect. The deformation mechanism appears different degrees of influence due to surface defects. The surface defects play a role of dislocation sources. Comparing with single intrinsic stacking faults formation for the perfect nanowire, much affluent deformation processes have been activated because of surface defects, for instance, we find the twins formation for the nanowire with a surface 45o defect.

The role of idea novelty and relatedness in nascent ventures

The study of venture idea characteristics and the contextual fit between venture ideas and individuals are key research goals in entrepreneurship (Davidsson, 2004). However, to date there has been limited scholarly attention given to these phenomena. Accordingly, this study aims to help fill the gap by investigating the importance of novelty and relatedness of venture ideas in entrepreneurial firms. On the premise that new venture creation is a process and that research should be focused on the early stages of the venturing process, this study primarily focuses its attention on examining how venture idea novelty and relatedness affect the performance in the venture creation process. Different types and degrees of novelty are considered here. Relatedness is shown to be based on individuals’ prior knowledge and resource endowment. Performance in the venture creation process is evaluated according to four possible outcomes: making progress, getting operational, being terminated and achieving positive cash flow. A theoretical model is developed demonstrating the relationship between these variables along with the investment of time and money. Several hypotheses are developed to be tested. Among them, it is hypothesised that novelty hinders short term performance in the venture creation process. On the other hand knowledge and resource relatedness are hypothesised to promote performance. An experimental study was required in order to understand how different types and degrees of novelty and relatedness of venture ideas affect the attractiveness of venture ideas in the eyes of experienced entrepreneurs. Thus, the empirical work in this thesis was based on two separate studies. In the first one, a conjoint analysis experiment was conducted on 32 experienced entrepreneurs in order to ascertain attitudinal preferences regarding venture idea attractiveness based on novelty, relatedness and potential financial gains. This helped to estimate utility values for different levels of different attributes of venture ideas and their relative importance in the attractiveness. The second study was a longitudinal investigation of how venture idea novelty and relatedness affect the performance in the venture creation process. The data for this study is from the Comprehensive Australian Study for Entrepreneurial Emergence (CAUSEE) project that has been established in order to explore the new venture creation process in Australia. CAUSEE collects data from a representative sample of over 30,000 households in Australia using random digit dialling (RDD) telephone interviews. From these cases, data was collected at two points in time during a 12 month period from 493 firms, who are currently involved in the start-up process. Hypotheses were tested and inferences were derived through descriptive statistics, confirmatory factor analysis and structural equation modelling. Results of study 1 indicate that venture idea characteristics have a role in the attractiveness and entrepreneurs prefer to introduce a moderate degree of novelty across all types of venture ideas concerned. Knowledge relatedness is demonstrated to be a more significant factor in attractiveness than resource relatedness. Results of study 2 show that the novelty hinders nascent venture performance. On the other hand, resource relatedness has a positive impact on performance unlike knowledge relatedness which has none. The results of these studies have important implications for potential entrepreneurs, investors, researchers, consultants etc. by developing a better understanding in the venture creation process and its success factors in terms of both theory and practice.