Shifting the technology context : career-change entrants’ transition into teaching

Becoming a teacher in technology-rich classrooms is a complex and challenging transition for career-change entrants. Those with generic or specialist Information and Communication Technology (ICT) expertise bring a mindset about purposeful uses of ICT that enrich student learning and school communities. The transition process from a non-education environment is both enhanced and constrained by shifting the technology context of generic or specialist ICT expertise, developed through a former career as well as general life experience. In developing an understanding of the complexity of classrooms and creating a learner centred way of working, perceptions about learners and learning evolve and shift. Shifts in thinking about how ICT expertise supports learners and enhances learning preceded shifts in perceptions about being a teacher, working with colleagues, and functioning in schools that have varying degrees of intensity and impact on evolving professional identities. Current teacher education and school induction programs are seen to be falling short of meeting the needs of career-change entrants and, as a flow on, the students they nurture. Research (see, for example, Tigchelaar, Brouwer, & Korthagen, 2008; Williams & Forgasz, 2009) highlights the value of generic and specialist expertise career-change teachers bring to the profession and draws attention to the challenges such expertise begets (Anthony & Ord, 2008; Priyadharshini & Robinson-Pant, 2003). As such, the study described in this thesis investigated perceptions of career-change entrants, who have generic (Mishra & Koehler, 2006) or specialist expertise, that is, ICT qualifications and work experience in the use of ICT. The career-change entrants‘ perceptions were sought as they shifted the technology context and transitioned into teaching in technology-rich classrooms. The research involved an interpretive analysis of qualitative data and quantitative data. The study used the explanatory case study (Yin, 1994) methodology enriched through grounded theory processes (Strauss & Corbin, 1998), to develop a theory about professional identity transition from the perceptions of the participants in the study. The study provided insights into the expertise and experiences of career change entrants, particularly in relation to how professional identities that include generic and specialist ICT knowledge and expertise were reconfigured while transitioning into the teaching profession. This thesis presents the Professional Identity Transition Theory that encapsulates perceptions about teaching in technology-rich classrooms amongst a selection of the increasing number of career-change entrants. The theory, grounded in the data, (Strauss & Corbin, 1998) proposes that career-change entrants experience transition phases of varying intensity that impact on professional identity, retention and development as a teacher. These phases are linked to a shift in perceptions rather than time as a teacher. Generic and specialist expertise in the use of ICT is a weight of the past and an asset that makes the transition process more challenging for career-change entrants. The study showed that career-change entrants used their experiences and perceptions to develop a way of working in a school community. Their way of working initially had an adaptive orientation focussed on immediate needs as their teaching practice developed. Following a shift of thinking, more generative ways of working focussed on the future emerged to enable continual enhancement and development of practice. Sustaining such learning is a personal, school and systemic challenge for the teaching profession.

Instability prolongs the chondral phase during bone healing in sheep

In this sheep study, we investigated the influence of fixation stability on the temporal and spatial distribution of tissues in the fracture callus. As the initial mechanical conditions have been cited as being especially important for the healing outcome, it was hypothesized that differences in the path of healing would be seen as early as the initial phase of healing. ----- ----- Sixty-four sheep underwent a mid-shaft tibial osteotomy that was treated with either a rigid or a semi-rigid external fixator. Animals were sacrificed at 2, 3, 6 and 9 weeks postoperatively and the fracture calluses were analyzed using radiological, biomechanical and histological techniques. Statistical comparison between the groups was performed using the Mann–Whitney U test for unpaired non-parametric data. ----- ----- In the callus of the tibia treated with semi-rigid fixation, remnants of the fracture haematoma remained present for longer, although new periosteal bone formation during early healing was similar in both groups. The mechanical competence of the healing callus at 6 weeks was inferior compared to tibiae treated with rigid fixation. Semi-rigid fixation resulted in a larger cartilage component of the callus, which persisted longer. Remodeling processes were initiated earlier in the rigid group, while new bone formation continued throughout the entire investigated period in the semi-rigid group. ----- ----- In this study, evidence is provided that less rigid fixation increased the time required for healing. The process of intramembranous ossification appeared during the initial stages of healing to be independent of mechanical stability. However, the delay in healing was related to a prolonged chondral phase.

Mechanical conditions in the initial phase of bone healing

Background: Bone healing is sensitive to the initial mechanical conditions with tissue differentiation being determined within days of trauma. Whilst axial compression is regarded as stimulatory, the role of interfragmentary shear is controversial. The purpose of this study was to determine how the initial mechanical conditions produced by interfragmentary shear and torsion differ from those produced by axial compressive movements. ----- ----- Methods: The finite element method was used to estimate the strain, pressure and fluid flow in the early callus tissue produced by the different modes of interfragmentary movement found in vivo. Additionally, tissue formation was predicted according to three principally different mechanobiological theories. ----- ----- Findings: Large interfragmentary shear movements produced comparable strains and less fluid flow and pressure than moderate axial interfragmentary movements. Additionally, combined axial and shear movements did not result in overall increases in the strains and the strain magnitudes were similar to those produced by axial movements alone. Only when axial movements where applied did the non-distortional component of the pressure–deformation theory influence the initial tissue predictions. ----- ----- Interpretation: This study found that the mechanical stimuli generated by interfragmentary shear and torsion differed from those produced by axial interfragmentary movements. The initial tissue formation as predicted by the mechanobiological theories was dominated by the deformation stimulus.

Re-engineering project planning processes : a best practice model for managing project phase integration issues

Competitive markets are increasingly driving new initiatives for shorter cycle times resulting in increased overlapping of project phases. This, in turn, necessitates improving the interfaces between the different phases to be overlapped (integrated), thus allowing transfer of processes, information and knowledge from one individual or team to another. This transfer between phases, within and between projects, is one of the basic challenges to the philosophy of project management. To make the process transfer more transparent with minimal loss of momentum and project knowledge, this paper draws upon Total Quality Management (TQM) and Business Process Re-engineering (BPR) philosophies to develop a Best Practice Model for managing project phase integration. The paper presents the rationale behind the model development and outlines its two key parts; (1) Strategic Framework and (2) Implementation Plan. Key components of both the Strategic Framework and the Implementation Plan are presented and discussed.

A new unequal DC link voltage configuration for a single phase multilevel converter to reduce low order harmonics

Multilevel converters are used in high power and high voltage applications due to their attractive benefits in generating high quality output voltage. Increasing the number of voltage levels can lead to a reduction in lower order harmonics. Various modulation and control techniques are introduced for multilevel converters like Space Vector Modulation (SVM), Sinusoidal Pulse Width Modulation (SPWM) and Harmonic Elimination (HE) methods. Multilevel converters may have a DC link with equal or unequal DC voltages. In this paper a new modulation technique based on harmonic elimination method is proposed for those multilevel converters that have unequal DC link voltages. This new technique has better effect on output voltage quality and less Total Harmonic Distortion (THD) than other modulation techniques. In order to verify the proposed modulation technique, MATLAB simulations are carried out for a single-phase diode-clamped inverter.

Numerical study of two ill-posed one-phase Stefan problems

We treat two related moving boundary problems. The first is the ill-posed Stefan problem for melting a superheated solid in one Cartesian coordinate. Mathematically, this is the same problem as that for freezing a supercooled liquid, with applications to crystal growth. By applying a front-fixing technique with finite differences, we reproduce existing numerical results in the literature, concentrating on solutions that break down in finite time. This sort of finite-time blow-up is characterised by the speed of the moving boundary becoming unbounded in the blow-up limit. The second problem, which is an extension of the first, is proposed to simulate aspects of a particular two-phase Stefan problem with surface tension. We study this novel moving boundary problem numerically, and provide results that support the hypothesis that it exhibits a similar type of finite-time blow-up as the more complicated two-phase problem. The results are unusual in the sense that it appears the addition of surface tension transforms a well-posed problem into an ill-posed one.

A Raman spectroscopic study of bukovskýite Fe2(AsO4)(SO4)(OH)•7H2O-a mineral phase with a significant role in arsenic migration

The Raman spectrum of bukovskýite, Fe3+2(OH)(SO4)(AsO4)•7H2O has been studied and compared with the Raman spectrum of an amorphous gel containing specifically Fe, As and S elements and is understood as an intermediate product in the formation of bukovskýite. Observed bands are assigned to the stretching and bending vibrations of (SO4)2- and (AsO4)3- units, stretching and bending vibrations and librational modes of hydrogen bonded water molecules, stretching and bending vibrations of hydrogen bonded (OH)- ions and Fe3+-(O,OH) units. Approximate range of O-H...O hydrogen bond lengths is inferred from the Raman spectra. Raman spectra of crystalline bukovskýite and of the amorphous gel differ in that the bukovskýite spectrum is more complex, observed bands are sharp, the degenerate bands of (SO4)2- and (AsO4)3- are split and more intense. Lower wavenumbers of  H2O bending vibration in the spectrum of the amorphous gel may indicate the presence of weaker hydrogen bonds compared with those in bukovskýite.

A collagen network phase improves cell seeding of open-pore structure scaffolds under perfusion

Scaffolds with open-pore morphologies offer several advantages in cell-based tissue engineering, but their use is limited by a low cell seeding efficiency. We hypothesized that inclusion of a collagen network as filling material within the open-pore architecture of polycaprolactone-tricalcium phosphate (PCL-TCP) scaffolds increases human bone marrow stromal cells (hBMSC) seeding efficiency under perfusion and in vivo osteogenic capacity of the resulting constructs. PCL-TCP scaffolds, rapid prototyped with a honeycomb-like architecture, were filled with a collagen gel and subsequently lyophilized, with or without final crosslinking. Collagen-free scaffolds were used as controls. The seeding efficiency was assessed after overnight perfusion of expanded hBMSC directly through the scaffold pores using a bioreactor system. By seeding and culturing freshly harvested hBMSC under perfusion for 3 weeks, the osteogenic capacity of generated constructs was tested by ectopic implantation in nude mice. The presence of the collagen network, independently of the crosslinking process, significantly increased the cell seeding efficiency (2.5-fold), and reduced the loss of clonogenic cells in the supernatant. Although no implant generated frank bone tissue, possibly due to the mineral distribution within the scaffold polymer phase, the presence of a non crosslinked collagen phase led to in vivo formation of scattered structures of dense osteoids. Our findings verify that the inclusion of a collagen network within open morphology porous scaffolds improves cell retention under perfusion seeding. In the context of cell-based therapies, collagen-filled porous scaffolds are expected to yield superior cell utilization, and could be combined with perfusion-based bioreactor devices to streamline graft manufacture.