Analytical and numerical solutions of the space and time fractional bloch-torrey equation

Fractional order dynamics in physics, particularly when applied to diffusion, leads to an extension of the concept of Brown-ian motion through a generalization of the Gaussian probability function to what is termed anomalous diffusion. As MRI is applied with increasing temporal and spatial resolution, the spin dynamics are being examined more closely; such examinations extend our knowledge of biological materials through a detailed analysis of relaxation time distribution and water diffusion heterogeneity. Here the dynamic models become more complex as they attempt to correlate new data with a multiplicity of tissue compartments where processes are often anisotropic. Anomalous diffusion in the human brain using fractional order calculus has been investigated. Recently, a new diffusion model was proposed by solving the Bloch-Torrey equation using fractional order calculus with respect to time and space (see R.L. Magin et al., J. Magnetic Resonance, 190 (2008) 255-270). However effective numerical methods and supporting error analyses for the fractional Bloch-Torrey equation are still limited. In this paper, the space and time fractional Bloch-Torrey equation (ST-FBTE) is considered. The time and space derivatives in the ST-FBTE are replaced by the Caputo and the sequential Riesz fractional derivatives, respectively. Firstly, we derive an analytical solution for the ST-FBTE with initial and boundary conditions on a finite domain. Secondly, we propose an implicit numerical method (INM) for the ST-FBTE, and the stability and convergence of the INM are investigated. We prove that the implicit numerical method for the ST-FBTE is unconditionally stable and convergent. Finally, we present some numerical results that support our theoretical analysis.

Mass transfer properties (permeability and mass diffusivity) of four australian hardwood species

Characterization of mass transfer properties was achieved in the longitudinal, radial, and tangential directions for four Australian hardwood species: spotted gum, blackbutt, jarrah, and messmate. Measurement of mass transfer properties for these species was necessary to complement current vacuum drying modeling research. Water-vapour diffusivity was determined in steady state using a specific vapometer. Permeability was determined using a specialized device developed to measure over a wide range of permeability values. Permeability values of some species and material directions were extremely low and undetectable by the mass flow meter device. Hence, a custom system based on volume evolution was conceived to determine very low, previously unpublished, wood permeability values. Mass diffusivity and permeability were lowest for spotted gum and highest for messmate. Except for messmate in the radial direction, the four species measured were less permeable in all directions than the lowest published figures, demonstrating the high impermeability of Australian hardwoods and partly accounting for their relatively slow drying rates. Permeability, water-vapour diffusivity, and associated anisotropic ratio data obtained for messmate were extreme or did not follow typical trends and is consequently the most difficult of the four woods to dry in terms of collapse and checking degradation. © The State of Queensland, Department of Agriculture, Fisheries and Forestry, 2012.

Motivators and barriers to incorporating climate change-related health risks in environmental health impact assessment

Climate change presents risks to health that must be addressed by both decision-makers and public health researchers. Within the application of Environmental Health Impact Assessment (EHIA), there have been few attempts to incorporate climate change-related health risks as an input to the framework. This study used a focus group design to examine the perceptions of government, industry and academic specialists about the suitability of assessing the health consequences of climate change within an EHIA framework. Practitioners expressed concern over a number of factors relating to the current EHIA methodology and the inclusion of climate change-related health risks. These concerns related to the broad scope of issues that would need to be considered, problems with identifying appropriate health indicators, the lack of relevant qualitative information that is currently incorporated in assessment and persistent issues surrounding stakeholder participation. It was suggested that improvements are needed in data collection processes, particularly in terms of adequate communication between environmental and health practitioners. Concerns were raised surrounding data privacy and usage, and how these could impact on the assessment process. These findings may provide guidance for government and industry bodies to improve the assessment of climate change-related health risks.

Performing design: game design, practice, praxis and the theatre of the impressed

This paper is a reflection on a design teaching project that endeavours to establish a culture of critical design thinking in a tertiary game design course. In the first instance, the ‘performing design’ project arose as a response to contemporary issues and tensions in the Australian games industry and game design education, in essence, the problem of how to scaffold undergraduate students from their entry point as ‘players’ (the impressed) into becoming designers. The performing design project therefore started as a small-scale intervention to inspire reflection in a wider debate that includes: the potential evolution of the contemporary games industry; the purpose of game design education; and the positioning of game design as a design discipline. Our position is that designing interactive playful works or games is victim of a tendency to simplify the discipline and view it from either the perspective of science or art. In this paper we look at some of the historical discussions on the distinct identity of games. Then we present an overview of the typical state of play in contemporary game design education which inspires the performing design project as an intervention or teaching technique. This leads us to question understandings of education and training and creativity and innovation. Finally we reflect on insights arising from the performing design project which lead us to support Archer’s call for a ‘third area’ that balances the monolithic practices of the two major academic disciplines.

Evaluation of implementation of a healthy food and drink supply strategy throughout the whole school environment in Queensland state schools, Australia

BACKGROUND/OBJECTIVES: This paper reports on the evaluation of the Smart Choices healthy food and drink supply strategy for Queensland schools (Smart Choices) implementation across the whole school environment in state government primary and secondary schools in Queensland, Australia. SUBJECTS/METHODS: Three concurrent surveys using different methods for each group of stakeholders that targeted all 1275 school Principals, all 1258 Parent and Citizens’ Associations (P&Cs) and a random sample of 526 tuckshop convenors throughout Queensland. Nine hundred and seventy-three Principals, 598 P&Cs and 513 tuckshop convenors participated with response rates of 78%, 48% and 98%, respectively. RESULTS: Nearly all Principals (97%), P&Cs (99%) and tuckshop convenors (97%) reported that their school tuckshop had implemented Smart Choices. The majority of Principals and P&Cs reported implementation, respectively, in: school breakfast programs (98 and 92%); vending machine stock (94 and 83%); vending machine advertising (85 and 84%); school events (87 and 88%); school sporting events (81 and 80%); sponsorship and advertising (93 and 84%); fundraising events (80 and 84%); and sporting clubs (73 and 75%). Implementation in curriculum activities, classroom rewards and class parties was reported, respectively, by 97%, 86% and 75% of Principals. Respondents also reported very high levels of understanding of Smart Choices and engagement of the school community. CONCLUSIONS: The results demonstrated that food supply interventions to promote nutrition across all domains of the school environment can be implemented successfully.

The impact of penalty increases on speeding behaviour in Queensland and a characterisation of speeding offenders

This project examined the effects of speeding penalty changes that occurred in Queensland in 2003 on the behaviour of speeding offenders. These penalty changes included increasing the number of offence categories, and in turn narrowing the range of speeds associated with the offence categories; increasing the monetary fines for all offences, with the largest increases observed for high-range offences; and introducing automatic licence suspension and an eight demerit point penalty for the highest offence category. To explore the impact of the penalty changes, offence data collected for two cohorts of motorists in Queensland who were caught speeding prior to and subsequent to the penalty changes (N = 84,456) were compared. The first cohort consisted of individuals (operators of all vehicles including motorcycles) who committed a speeding offence in May 2001 (two years prior to the speeding penalty change); and individuals who committed a speeding offence in May 2003 (one month after the introduction of the penalty change). Four measures of recidivism were devised and used to assess the effects of the new penalties with regard to deterring the speeding behaviour of offenders. Additionally, the project investigated the relationship between speeding offences, other risky driving behaviours, crash involvement, and criminal behaviour.

Factors affecting two- and five-year re-offence rates in Queensland drink drivers

Risk factors for repeat drink driving, an important road safety issue, are well known, but estimates of Australian recidivism rates by risk factors, apart from a recent NSW study, are not. Driving records of a cohort of Queensland drink drivers matched by age, region, BAC level and prior offence to participants in a drink driving rehabilitation program were used to estimate sex-specific two- and five-year re-offence rates overall and by these factors. Estimates of the proportion of Queensland drink drivers with a prior DD offence in 2004 were used to standardise rates to the Queensland drink driving population. Rates were higher in remote areas, as were rates in males, young drivers, drivers with high BAC levels and in drivers with one and especially with at least two prior DD convictions. Five-year rates for Queensland were estimated as 21.8% in males and 16.4% in females, appreciably higher than in NSW.

Curriculum design and higher order skills : challenging assumptions

This paper is based on an Australian Learning & Teaching Council (ALTC) funded evaluation in 13 universities across Australia and New Zealand of the use of Engineers Without Borders (EWB) projects in first-year engineering courses. All of the partner institutions have implemented this innovation differently and comparison of these implementations affords us the opportunity to assemble "a body of carefully gathered data that provides evidence of which approaches work for which students in which learning environments". This study used a mixed-methods data collection approach and a realist analysis. Data was collected by program logic analysis with course co-ordinators, observation of classes, focus groups with students, exit survey of students and interviews with staff as well as scrutiny of relevant course and curriculum documents. Course designers and co-ordinators gave us a range of reasons for using the projects, most of which alluded to their presumed capacity to deliver experience in and learning of higher order thinking skills in areas such as sustainability, ethics, teamwork and communication. For some students, however, the nature of the projects decreased their interest in issues such as ethical development, sustainability and how to work in teams. We also found that the projects provoked different responses from students depending on the nature of the courses in which they were embedded (general introduction, design, communication, or problem-solving courses) and their mode of delivery (lecture, workshop or online).

Pre-service teachers' pedagogical relationships and experiences of embedding Indigenous Australian knowledge in teaching practicum

This paper argues from the standpoint that embedding Indigenous knowledge and perspectives in Australian curricula occurs within a space of tension, ‘the cultural interface’ (Nakata, 2002), in negotiation and contestation with other dominant knowledge systems. In this interface, Indigenous knowledge (IK) is in a state of constancy and flux, invisible and simultaneously pronounced depending on the teaching and learning contexts. More often than not, IK competes for validity and is vexed by questions of racial and cultural authenticity, and therefore struggles to be located centrally in educational systems, curricula and pedagogies. Interrogating normative western notions of what constitutes authentic or legitimate knowledge is critical to teaching Indigenous studies and embedding IK. The inclusion (and exclusion) of IK at the interface is central to developing curriculum that allows teachers to test and prod, create new knowledge and teaching approaches. From this perspective, we explore Indigenous Australian pre-service teachers’ experiences of pedagogical relationships within the teaching habitus of Australian classrooms. Our study is engaged with the strategic transgressions of praxis. We contend that tensions that participant Indigenous Australian pre-service teachers experience mirror the broader (and unresolved) political status of Indigenous people and thus where and why IK is strategically deployed as ‘new’ or ‘old knowledge within Australian liberal democratic systems of curriculum and schooling. It is significant to discuss the formation and transformation of the pedagogical cultural identity of the teaching profession within which Indigenous and non-Indigenous pre-service teachers are employed.