The effect of diverse development goals on computer-based system dependability

PhD ThesisSociety's increasing dependence upon software control and information process- ing provision has demanded comparable increases in software dependability. While the existing software dependability approach has resulted in significant improve- ments, its focus is heavily aimed towards achieving software dependability via redundant fault-tolerant mechanisms built into the software artifact to provide error-control in the presence of activated faults. Less emphasis appears to have been placed upon how software dependability can also be promoted through a fault-avoidance approach in the software creation process by incorporating hu- man redundancy and diversity. In this thesis, a process intervention which can potentially improve fault-avoidance is considered. This involves the setting of diverse development goals within important generic computer-based system con- texts in order to increase detection of potentially harmful assumptions which can result in subtle systemic conflicts that can undermine the dependability of the re- sultant artifact during the early development phases of requirements, specification and design. A search theoretic simulation model is progressed and developed to capture some of the important dynamics involved. The eventual outputs of the simulation model indicate that increased fault coverage and sensitivity can be ob- tained through the setting of diverse development goals during the early phases of software development.EPSR

Preparing Christian health workers for international work: Evaluating a short global health course

Improving global health education to ensure health professionals are prepared and competent in the world's increasingly interconnected health-scape is a vital need. For many health professionals, global health education is facilitated through short, pre-departure courses in cross-cultural health and development work. There is currently limited literature on both the availability and the effectiveness of such courses. Our research aim was to explore the impact of a short course in global health education, designed and delivered by an Australian not-for-profit organisation, Intermed SA (Intermed). We conducted a short online survey of Intermed graduates, followed by semi-structured interviews with selected participants. The results indicate that Intermed's International Health and Development course was effective in achieving the course objectives as assessed by graduates, whilst also having a positive practical impact on the graduates' professional development

Student conceptions about energy transformations: progression from general chemistry to biochemistry

Students commencing studies in biochemistry must transfer and build on concepts they learned in chemistry and biology classes. It is well established, however, that students have difficulties in transferring critical concepts from general chemistry courses; one key concept is “energy.” Most previous work on students’ conception of energy has focused on their understanding of energy in the context of physics (including the idea of “work”) and/or their understanding of energy in classical physical and inorganic chemistry contexts (particularly Gibbs Free Energy changes, the second law of thermodynamics, and equilibrium under standard conditions within a closed system). For biochemistry, students must go beyond those basic thermodynamics concepts of work, standard energy changes, and closed systems, and instead they must consider what energy flow, use, and transformation mean in living, open, and dynamic systems. In this study we explored students’ concepts about free energy and flow in biological chemical reactions and metabolic pathways by surveys and in-depth interviews. We worked with students in general chemistry classes and biochemistry courses in both an Australian and a US tertiary institution. We address three primary questions (i) What are the most common alternative conceptions held by students when they explain energy-related phenomena in biochemistry?, (ii) What information do students transfer from introductory chemistry and biology when they are asked to consider energy in a biological reaction or reaction pathway?, and (iii) How do students at varying levels of competence articulate their understandings of energy in pathways and biological reactions? The answers to these questions are used to build a preliminary learning progression for understanding “energy” in biochemistry. We also propose crucial elements of content knowledge that instructors could apply to help students better grasp this threshold concept in biochemistry

Plant exudates may stabilize or weaken soil depending on species, origin and time

We hypothesized that plant exudates could either gel or disperse soil depending on their chemical characteristics. Barley (Hordeum vulgare L. cv. Optic) and maize (Zea mays L.cv. Freya) root exudates were collected using an aerated hydroponic method and compared to chia (Salvia hispanica L.) seed exudate, a commonly used root exudate analogue. Sandy loam soil passed through a 500-μm mesh was treated with each exudate at a concentrationof 4.6 mg exudate g-1 dry soil. Two sets of soil samples were prepared, One set of treated soil samples was maintained at 4oC to suppress microbial processes. To characterize the effect of decomposition, the second set of samples was incubated at 16C for 2 weeks at – 30 kPa matric potential. Gas chromatography–mass spectrometry (GC–MS) analysis of the exudates found that barley had the largest organic acid content and chia the largest content of sugars (polysaccharide-derived or free), and maize was in between barley and chia. Yield stress of amended soil samples was measured by an oscillatory strain sweep test with a cone plate rheometer. When microbial decomposition was suppressed at 4oC, yield stress increased 20-fold for chia seed exudate and two-fold for maize root exudate compared to the control, whereas for barley root exudate it decreased to half. The yield stress after 2 weeks of incubation compared to soil with suppressed microbial decomposition increased by 85% for barley root exudate, but for chia and maize it decreased to by 87% and 54%, respectively. Barley root exudation might therefore disperse soil and this could facilitate nutrient release. The maize root and chia seed exudates gelled soil, which could create a more stable soil structure around roots or seeds

Australian general practice trainees’ exposure to ophthalmic problems and implications for training: A cross-sectional analysis

INTRODUCTION: Eye conditions are common presentations in Australian general practice, with the potential for serious sequelae. Pre-vocational ophthalmology training for General Practitioner (GP) trainees is limited. AIM: To describe the rate, nature and associations of ophthalmic problems managed by Australian GP trainees, and derive implications for education and training. METHODS: Cross-sectional analysis from an ongoing cohort study of GP trainees’ clinical consultations. Trainees recorded demographic, clinical and educational details of consecutive patient consultations. Descriptive analyses report trainee, patient and practice demographics. Proportions of all problems managed in these consultations that were ophthalmology-related were calculated with 95% confidence intervals (CI). Associations were tested using simple logistic regression within the generalised estimating equations (GEE) framework. RESULTS: In total, 884 trainees returned data on 184,476 individual problems or diagnoses from 118,541 encounters. There were 2649 ophthalmology-related problems, equating to 1.4% (95% CI: 1.38-1.49) of all problems managed. The most common eye presentations were conjunctivitis (32.5% of total problems), eyelid problems (14.9%), foreign body (5.3%) and dry eye (4.7%). Statistically significant associations were male trainee; male patient and patient aged 14 years or under; the problem being new and the patient being new to both trainee and practice; urban and of higher socioeconomic status practice location; the practice nurse not being involved; planned follow up not arranged; referral made; in-consultation information sought; and learning goals generated. DISCUSSION: Trainees have comparable ophthalmology exposure to established GPs. However, associations with referral and information-seeking suggest GP trainees find ophthalmic problems challenging, reinforcing the critical importance of appropriate training

Imaging microstructure of the barley rhizosphere:particle packing and root hair influences

Soil adjacent to roots has distinct structural and physical properties from bulk soil, affecting water and solute acquisition by plants. Detailed knowledge on how root activity and traits such as root hairs affect the three-dimensional pore structure at a fine scale is scarce and often contradictory. Roots of hairless barley (Hordeum vulgare L. cv Optic) mutant (NRH) and its wildtype (WT) parent were grown in tubes of sieved (&lt;250 μm) sandy loam soil under two different water regimes. The tubes were scanned by synchrotron-based X-ray computed tomography to visualise pore structure at the soil–root interface. Pore volume fraction and pore size distribution were analysed vs distance within 1 mm of the root surface. Less dense packing of particles at the root surface was hypothesised to cause the observed increased pore volume fraction immediately next to the epidermis. The pore size distribution was narrower due to a decreased fraction of larger pores. There were no statistically significant differences in pore structure between genotypes or moisture conditions. A model is proposed that describes the variation in porosity near roots taking into account soil compaction and the surface effect at the root surface.</p

A cryogenic rotation stage with a large clear aperture for the half-wave plates in the Spider instrument

We describe the cryogenic half-wave plate rotation mechanisms built for and used in Spider, a polarization-sensitive balloon-borne telescope array that observed the Cosmic Microwave Background at 95 GHz and 150 GHz during a stratospheric balloon flight from Antarctica in January 2015. The mechanisms operate at liquid helium temperature in flight. A three-point contact design keeps the mechanical bearings relatively small but allows for a large (305 mm) diameter clear aperture. A worm gear driven by a cryogenic stepper motor allows for precise positioning and prevents undesired rotation when the motors are depowered. A custom-built optical encoder system monitors the bearing angle to an absolute accuracy of +/- 0.1 degrees. The system performed well in Spider during its successful 16 day flight.Comment: 11 pages, 7 figures, Published in Review of Scientific Instruments. v2 includes reviewer changes and longer literature revie

Addition of four doses of rituximab to standard induction chemotherapy in adult patients with precursor B-cell acute lymphoblastic leukaemia (UKALL14): a phase 3, multicentre, randomised controlled trial

BACKGROUND: Treatment for adults with acute lymphoblastic leukaemia requires improvement. UKALL14 was a UK National Cancer Research Institute Adult ALL group study that aimed to determine the benefit of adding the anti-CD20 monoclonal antibody, rituximab, to the therapy of adults with de novo B-precursor acute lymphoblastic leukaemia. METHODS: This was an investigator-initiated, phase 3, randomised controlled trial done in all UK National Health Service Centres treating patients with acute lymphoblastic leukaemia (65 centres). Patients were aged 25-65 years with de-novo BCR-ABL1-negative acute lymphoblastic leukaemia. Patients with de-novo BCR-ABL1-positive acute lymphoblastic leukaemia were eligible if they were aged 19-65 years. Participants were randomly assigned (1:1) to standard-of-care induction therapy or standard-of-care induction therapy plus four doses of intravenous rituximab (375 mg/m2 on days 3, 10, 17, and 24). Randomisation used minimisation and was stratified by sex, age, and white blood cell count. No masking was used for patients, clinicians, or staff (including the trial statistician), although the central laboratory analysing minimal residual disease and CD20 was masked to treatment allocation. The primary endpoint was event-free survival in the intention-to-treat population. Safety was assessed in all participants who started trial treatment. This study is registered with ClincialTrials.gov, NCT01085617. FINDINGS: Between April 19, 2012, and July 10, 2017, 586 patients were randomly assigned to standard of care (n=292) or standard of care plus rituximab (n=294). Nine patients were excluded from the final analysis due to misdiagnosis (standard of care n=4, standard of care plus rituximab n=5). In the standard-of-care group, median age was 45 years (IQR 22-65), 159 (55%) of 292 participants were male, 128 (44%) were female, one (<1%) was intersex, and 143 (59%) of 244 participants had high-risk cytogenetics. In the standard-of-care plus rituximab group, median age was 46 years (IQR 23-65), 159 (55%) of 294 participants were male, 130 (45%) were female, and 140 (60%) of 235 participants had high-risk cytogenetics. After a median follow-up of 53·7 months (IQR 40·3-70·4), 3-year event-free survival was 43·7% (95% CI 37·8-49·5) for standard of care versus 51·4% (45·4-57·1) for standard of care plus rituximab (hazard ratio [HR] 0·85 [95% CI 0·69-1·06]; p=0·14). The most common adverse events were infections and cytopenias, with no difference between the groups in the rates of adverse events. There were 11 (4%) fatal (grade 5) events in induction phases 1 and 2 in the standard-of-care group and 13 (5%) events in the standard-of-care plus rituximab group). 3-year non-relapse mortality was 23·7% (95% CI 19·0-29·4) in the standard-of-care group versus 20·6% (16·2-25·9) in the standard-of-care plus rituximab group (HR 0·88 [95% CI 0·62-1·26]; p=0·49). INTERPRETATION: Standard of care plus four doses of rituximab did not significantly improve event-free survival over standard of care. Rituximab is beneficial in acute lymphoblastic leukaemia but four doses during induction is likely to be insufficient. FUNDING: Cancer Research UK and Blood Cancer UK

Feedback or feedforward: Supporting students with alternate or missing conceptions in chemistry as they transition into tertiary chemistry

Constructivist learning environments are most effective when the learner and teacher are both aware of the existing conceptual models that learners possess to enable them to extend and apply their understanding rather than resort to rote learning (Taber, 2001). As students transition into, and engage in, the new tertiary learning environment it is important to assist them to maximise the effectiveness of their learning which requires measurement or diagnosis of their existing conceptual understanding. One of the challenges in teaching chemistry is to encourage students to recognise their existing knowledge and conceptual understanding and then apply it in new learning situations (Schraw, Crippen, & Hartley, 2006). Feedback is particularly important for first-year students because they are coming to terms with the change of environment, expectations, teaching approaches and forms of assessment. In this context, Hattie and Timperley’s three questions (Hattie & Timerley, 2007) are particularly relevant: “Where am I going?”, “How am I going?” and “Where to next?” Formative assessment is critical to “How am I going?” and the feedback is just as valuable for the instructor as for the students to support student learning. REFERENCES Hattie, J., & Timperley, H. (2007). The Power of Feedback. Review of Educational Research. 77, 81-112. Schraw, G., Crippen, K. J., & Hartley, K. (2006). Promoting self-regulation in science education: Metacognition as part of a broader persepective on learning. Research in Science Education. 36, 111-39. Taber, K. S. (2001). The mismatch between assumed prior knowledge and the Learner’s conceptions: A typology of learning impediments. Educational Studies, 27, 159-71