Active regulation of the epidermal calcium profile

A distinct calcium profile is strongly implicated in regulating the multi-layered structure of the epidermis. However, the mechanisms that govern the regulation of this calcium profile are currently unclear. It clearly depends on the relatively impermeable barrier of the stratum corneum (passive regulation) but may also depend on calcium exchanges between keratinocytes and extracellular fluid (active regulation). Using a mathematical model that treats the viable sublayers of unwounded human and murine epidermis as porous media and assumes that their calcium profiles are passively regulated, we demonstrate that these profiles are also actively regulated. To obtain this result, we found that diffusion governs extracellular calcium motion in the viable epidermis and hence intracellular calcium is the main source of the epidermal calcium profile. Then, by comparison with experimental calcium profiles and combination with a hypothesised cell velocity distribution in the viable epidermis, we found that the net influx of calcium ions into keratinocytes from extracellular fluid may be constant and positive throughout the stratum basale and stratum spinosum, and that there is a net outflux of these ions in the stratum granulosum. Hence the calcium exchange between keratinocytes and extracellular fluid differs distinctly between the stratum granulosum and the underlying sublayers, and these differences actively regulate the epidermal calcium profile. Our results also indicate that plasma membrane dysfunction may be an early event during keratinocyte disintegration in the stratum granulosum

A continuum model of the growth of engineered epidermal skin substitutes

We present a porous medium model of the growth and deterioration of the viable sublayers of an epidermal skin substitute. It consists of five species: cells, intracellular and extracellular calcium, tight junctions, and a hypothesised signal chemical emanating from the stratum corneum. The model is solved numerically in Matlab using a finite difference scheme. Steady state calcium distributions are predicted that agree well with the experimental data. Our model also demonstrates epidermal skin substitute deterioration if the calcium diffusion coefficient is reduced compared to reported values in the literature

Preparing future graduates to become lifelong, expert learners: Lessons and considerations from a blended learning engineering mathematics unit

We present an investigation of the uptake of opportunities for learning provided by a specific component (pre-lecture videos) of a blended learning model. The model, presented in previous work of the authors, was implemented to improve students’ content and learning expertise in a foundation engineering mathematics subject. The ultimate goal of the model was to support future graduates becoming lifelong expert learners, facilitating their success in later studies in and after their degree. In particular, we investigated to what extent did the cohort take the opportunity to develop their expert learning skills as evidenced by pre-lecture video viewing, and what was the relationship between the identified behaviour and learners’ progression and achievement. We present findings based on an analysis of data sourced from the unit website and propose further questions for future research

Preparing future graduates to become lifelong, expert learners: lessons and considerations from a blended engineering mathematics unit

We present an investigation of the uptake of opportunities for learning provided by a specific component (pre-lecture videos) of a blended learning model. The model, presented in previous work of the authors, was implemented to improve students’ content and learning expertise in a foundation engineering mathematics subject. The ultimate goal of the model was to support future graduates becoming lifelong expert learners, facilitating their success in later studies in and after their degree. In particular, we investigated to what extent did the cohort take the opportunity to develop their expert learning skills as evidenced by pre-lecture video viewing, and what was the relationship between the identified behaviour and learners’ progression and achievement. We present findings based on an analysis of data sourced from the unit website and propose further questions for future research

A model of workplace safety incorporating worker interactions and simple interventions

Although there was substantial research into the occupational health and safety sector over the past forty years, this generally focused on statistical analyses of data related to costs and/or fatalities and injuries. There is a lack of mathematical modelling of the interactions between workers and the resulting safety dynamics of the workplace. There is also little work investigating the potential impact of different safety intervention programs prior to their implementation. In this article, we present a fundamental, differential equation-based model of workplace safety that treats worker safety habits similarly to an infectious disease in an epidemic model. Analytical results for the model, derived via phase plane and stability analysis, are discussed. The model is coupled with a model of a generic safety strategy aimed at minimising unsafe work habits, to produce an optimal control problem. The optimal control model is solved using the forward-backward sweep numerical scheme implemented in Matlab. References Australian Bureau of Statistics. Forms of employment. Commonwealth of Australia, 2010. http://www.abs.gov.au/AUSSTATS/[email protected]/DetailsPage/6359.0November%202010?OpenDocument Bahn, S. Power and Influence: Examining the Communication Pathways that Impact on Safety in the Workplace. J. Occup. Health Safety–-Aust. N.Z., 25(3):213–222, 2009. Bird, P. Reducing Manual Handling Workers Compensation Claims in a Public Health Facility. J. Occup. Health Safety–-Aust. N.Z., 25(6):451–459, 2009. Breslin, P. Improving ohs Standards in the Building and Construction Industry through safe design. J. Occup. Health Safety–-Aust. N.Z., 23(4):89–99, 2007. Breslin, P. National Harmonisation: Designers' Duties of Care in the Australian Building and Construction Industry. J. Occup. Health Safety–-Aust. N.Z., 25(6):495–504, 2009 . Driscoll, T., Mitchell, T., Mandryk, J., Healey, S., Hendrie, L. and Hull, B. Trends in Work-Related Fatalities in Australia, 1982 to 1992. J. Occup. Health Safety–-Aust. N.Z., 18(1):21–33, 2002. Driscoll, T. Fatal Injury of young workers in Australia. J. Occup. Health Safety–-Aust. N.Z., 22(2):151–161, 2006. Foley, G., Gale, J. and Gavenlock, L. The Cost of Work-Related Injury and Disease. J. Occup. Health Safety–-Aust. N.Z., 11(2):171–194, 1995. Glendon, I. and Waring, A. Risk management as a framework for occupational health and safety. J. Occup. Health Safety–-Aust. N.Z., 13(6):525–532, 1997. Gunningham, N. and Healy, P. Agricultural ohs Policy: Towards Systemic Reform. J. Occup. Health Safety–-Aust. N.Z., 20(4):311–318, 2004. Hawkins, A., Eather, J. and Fragar, L. Improving Health and Safety in the Farm Workshop. J. Occup. Health Safety–-Aust. N.Z., 24(2):155–160, 2008. Heads of Workers' Compensation Authorities. 2008/09 Australia and New Zealand Return to Work Monitor. http://www.hwca.org.au/documents/Australia%20and%20New%20Zealand%20Return%20to%20Work%20Monitor%202008-2009.pdf Kermack, W. O. and McKendrick, A. G. A Contribution to the Mathematical Theory of Epidemics. Proc. R. Soc. Lond. A., 115(772):700–721, 1927. doi:10.1098/rspa.1927.0118 Lenhart, S. and Workman, J. T. Optimal control applied to biological models. Chapman and Hall CRC Mathematical and Computational Biology Series, 2007. Mallet, D. G., Bagher-Oskouei, M., Farr, A. C., Simpson, D. P. and Sutton, K-J. A mathematical model of Chlamydial infection incorporating movement of Chlamydial particles. B. Math. Biol., 75(11):2257–2270, 2013. doi:10.1007/s11538-013-9891-9 Murray, J. D. Mathematical Biology, I: An Introduction. Springer, 2002. Raggett, G. F. Modelling the Eyam plague. B. I. Math. Appl., 18:221–226, 1982. Safe Work Australia. The cost of work-related injury and illness for australian employers, workers and the community:2008-2009. Commonwealth of Australia, 2012. http://www.safeworkaustralia.gov.au/sites/SWA/about/Publications/Documents/660/Cost%20of%20Work-related%20injury%20and%20disease.pdf Shulgin, B., Stone, L. and Agur, Z. Pulse vaccination strategy in the sir Epidemic Model. B. Math. Biol., 60(6):1123–1148, 1998. doi:10.1006/S0092-8240(98)90005-2 Vanderkruk, R. Workplace health and safety officers: a Queensland success story. J. Occup. Health Safety–-Aust. N.Z., 15(6):557–563, 1999. Winder, C. The development of ohs legislation in Australia. J. Occup. Health Safety–-Aust. N.Z., 25(4):277–287, 2009

Enhancing students' learning through a blended learning cycle for engineering mathematics

BACKGROUND This study responds to the need for developing effective teaching methods helping students with the acquisition of specific STEM skills (West, 2012, 2013). It applies principles of blended learning design (Saliba, et al. 2013), in the context of mathematics courses (Stevenson & Zweier, 2011; Calderon, et al., 2012; Carbonell, et al., 2013) with attention paid to the potential for use – affordances – (Gibson, 1977, 1979; Hartson, 2003; Good, 2007) of Information Communication Technologies (ICT) offered by e-learning environments (Kirschner, 2004; Kirschner et al., 2004). AIMS The overall goal of the study was to improve student engagement and satisfaction, by re-designing a 1st year engineering mathematics unit. Specific objectives included: (1) investigating ways of effectively using the online tool WeBWorK for mathematics competence diagnostics, (2) improving the delivery of face-to-face (f2f) lectures and tutorials by designing, developing and implementing activities that explicitly link f2f delivery with online components, and (3) improving 1st year student engagement by developing a model of close collaboration between the teaching team and student success and learning support programs. DESCRIPTION OF INTERVENTION Inspired by recent changes to the University’s learning and teaching vision, the authors anchored the unit’s re-design process in the blended learning methodology (Saliba, G. et al, 2013). Its principles were used to systematically evaluate the delivery modes and learning and teaching (L&T) methodologies of the unit, define areas for improvement, design and implement the changes and complete the first part of the study. More precisely, the changes included: (1) re-designing the unit’s online presence to be more efficient in providing students with a well-organized, structured L&T platform; (2) embedding online tools in the unit content; (3) designing and developing ‘challenge questions’ – activities making direct connection between theoretical content of the lecture with its practical applications during the f2f, small-group workshops, and (4) coordinating the actions of institutional learning support and student success programs to make the support visible to students. DESIGN AND METHODS The project used an action research approach to investigate the designed intervention’s effectiveness. A questionnaire composed of Likert-scale and open-ended questions was distributed at the end of semester to two cohorts of students (Summer 2013 and Semester 1 2014). Here we report on the data analysis focused on the students’ perception and the uptake of the potential for an action (affordances) offered by WeBWorK. The results allowed the designer and the teaching team to reflect on and re-think the ways the tools have been used in the unit, re-program the tool and implement the modified tool in Semester 2 2014. RESULTS Preliminary conclusion: The results of the data collected in phase 1 of the project indicated that students did not perceive full potential offered by the tool, therefore the possibility to enhance their engagement and satisfaction has not been entirely exploited. CONCLUSIONS Based on the data analysis, the authors formulated: (1) hypotheses for explaining the results and (2) possible improvements to be made in order to allow students to use more efficiently the potential offered by the tool. These will be discussed at the presentation along with the first observations made based on the implemented modifications

Towards a classification of criterion referenced assessment models in mathematics courses - student and academic perspectives

We present the findings of a study into the implementation of explicitly criterion- referenced assessment in undergraduate courses in mathematics. We discuss students' concepts of criterion referencing and also the various interpretations that this concept has among mathematics educators. Our primary goal was to move towards a classification of criterion referencing models in quantitative courses. A secondary goal was to investigate whether explicitly presenting assessment criteria to students was useful to them and guided them in responding to assessment tasks. The data and feedback from students indicates that while students found the criteria easy to understand and useful in informing them as to how they would be graded, it did not alter the way the actually approached the assessment activity

Solution methods for advection-diffusion-reaction equations on growing domains and subdomains, with application to modelling skin substitutes

Problems involving the solution of advection-diffusion-reaction equations on domains and subdomains whose growth affects and is affected by these equations, commonly arise in developmental biology. Here, a mathematical framework for these situations, together with methods for obtaining spatio-temporal solutions and steady states of models built from this framework, is presented. The framework and methods are applied to a recently published model of epidermal skin substitutes. Despite the use of Eulerian schemes, excellent agreement is obtained between the numerical spatio-temporal, numerical steady state, and analytical solutions of the model

Communicating assessment criteria is not sufficient for influencing students' approaches to assessment tasks - Perspectives from a Differential Equations Class

This report presents the findings of an exploratory study into the perceptions held by students regarding the use of criterion-referenced assessment in an undergraduate differential equations class. Students in the class were largely unaware of the concept of criterion referencing and of the various interpretations that this concept has among mathematics educators. Our primary goal was to investigate whether explicitly presenting assessment criteria to students was useful to them and guided them in responding to assessment tasks. Quantitative data and qualitative feedback from students indicates that while students found the criteria easy to understand and useful in informing them as to how they would be graded, the manner in which they actually approached the assessment activity was not altered as a result of the use of explicitly communicated grading criteria

An example of cognitive obstacles in advanced integration: the case of scalar line integrals

Cognitive obstacles that arise in the teaching and learning of scalar line integrals, derived from cognitive aids provided to students when first learning about integration of single variable functions are described. A discussion of how and why the obstacles cause students problems is presented and possible strategies to overcome the obstacles are outlined