Adaptive estimation of hidden semi-Markov chains with parameterised transition probabilities and exponential decaying states

This paper develops maximum likelihood (ML) estimation schemes for finite-state semi-Markov chains in white Gaussian noise. We assume that the semi-Markov chain is characterised by transition probabilities of known parametric from with unknown parameters. We reformulate this hidden semi-Markov model (HSM) problem in the scalar case as a two-vector homogeneous hidden Markov model (HMM) problem in which the state consist of the signal augmented by the time to last transition. With this reformulation we apply the expectation Maximumisation (EM ) algorithm to obtain ML estimates of the transition probabilities parameters, Markov state levels and noise variance. To demonstrate our proposed schemes, motivated by neuro-biological applications, we use a damped sinusoidal parameterised function for the transition probabilities.

Modeling conditional correlations of asset returns : a smooth transition approach

In this paper we propose a new multivariate GARCH model with time-varying conditional correlation structure. The time-varying conditional correlations change smoothly between two extreme states of constant correlations according to a predetermined or exogenous transition variable. An LM–test is derived to test the constancy of correlations and LM- and Wald tests to test the hypothesis of partially constant correlations. Analytical expressions for the test statistics and the required derivatives are provided to make computations feasible. An empirical example based on daily return series of five frequently traded stocks in the S&P 500 stock index completes the paper.

Onset of transition in mixed convection of a lid-driven trapezoidal enclosure filled with water-Al2O3 nanofluid

A numerical study is carried out to investigate the transition from laminar to chaos in mixed convection heat transfer inside a lid-driven trapezoidal enclosure. In this study, the top wall is considered as isothermal cold surface, which is moving in its own plane at a constant speed, and a constant high temperature is provided at the bottom surface. The enclosure is assumed to be filled with water-Al2O3 nanofluid. The governing Navier–Stokes and thermal energy equations are expressed in non-dimensional forms and are solved using Galerkin finite element method. Attention is paid in the present study on the pure mixed convection regime at Richandson number, Ri = 1. The numerical simulations are carried out over a wide range of Reynolds (0.1 ≤ Re ≤ 103) and Grashof (0.01 ≤ Gr ≤ 106) numbers. Effects of the presence of nanofluid on the characteristics of mixed convection heat transfer are also explored. The average Nusselt numbers of the heated wall are computed to demonstrate the influence of flow parameter variations on heat transfer. The corresponding change of flow and thermal fields is visualized from the streamline and the isotherm contour plots.

The professional socialisation of paramedics : the transition from intern to qualified paramedic

The professional socialisation of paramedics encompasses preconceptions developed during childhood and early adulthood, and subsequent changes in perceptions resulting from university studies, clinical placements and encountering the professional workplace as an employee. This study investigates the professional socialisation of university educated paramedics making the transition from paramedic intern to qualified paramedic. Participants were sought from several of Australia’s larger ambulance services and UK NHS Ambulance Trusts to take part in this study. Participants were recruited through Ambulance Service Research Institutes, Clinical Governance Departments and university databases. To be included in this study, participants were required to be university educated, have completed a professional internship year and achieved qualified or registered paramedic status. Data collection was via face to face semi-structured interviews. Transcripts were analysed using socialisation models from the nursing and allied health disciplines and a grounded theory approach. The study found that participants initially enjoyed their new professional status after completing their internship and becoming qualified paramedics. However, for many the excitement of becoming a qualified paramedic was short lived. Newly qualified paramedics experienced increased levels of responsibility and were required to develop mentoring skills while still adjusting to their new roles. Participants had to contend with inner conflicting views about the reality of paramedic work which were developed though preconceptions and experiences as paramedic interns. The transition from paramedic intern to qualified paramedic is reportedly a challenging experience, as newly qualified paramedics are required to deal with added complexities while still adjusting to their new roles.

Kallikrein 4 (hK4) and prostate-specific antigen (PSA) are associated with the loss of E-cadherin and an epithelial-mesenchymal transition (EMT)-like effect in prostate cancer cells

Prostate-specific antigen (PSA) and the related kallikrein family of serine proteases are current or emerging biomarkers for prostate cancer detection and progression. Kallikrein 4 (KLK4/hK4) is of particular interest, as KLK4 mRNA has been shown to be elevated in prostate cancer. In this study, we now show that the comparative expression of hK4 protein in prostate cancer tissues, compared with benign glands, is greater than that of PSA and kallikrein 2 (KLK2/hK2), suggesting that hK4 may play an important functional role in prostate cancer progression in addition to its biomarker potential. To examine the roles that hK4, as well as PSA and hK2, play in processes associated with progression, these kallikreins were separately transfected into the PC-3 prostate cancer cell line, and the consequence of their stable transfection was investigated. PC-3 cells expressing hK4 had a decreased growth rate, but no changes in cell proliferation were observed in the cells expressing PSA or hK2. hK4 and PSA, but not hK2, induced a 2.4-fold and 1.7-fold respective increase, in cellular migration, but not invasion, through Matrigel, a synthetic extracellular matrix. We hypothesised that this increase in motility displayed by the hK4 and PSA-expressing PC-3 cells may be related to the observed change in structure in these cells from a typical rounded epithelial-like cell to a spindle-shaped, more mesenchymal-like cell, with compromised adhesion to the culture surface. Thus, the expression of E-cadherin and vimentin, both associated with an epithelial-mesenchymal transition (EMT), was investigated. E-cadherin protein was lost and mRNA levels were significantly decreased in PC-3 cells expressing hK4 and PSA (10-fold and 7-fold respectively), suggesting transcriptional repression of E-cadherin, while the expression of vimentin was increased in these cells. The loss of E-cadherin and associated increase in vimentin are indicative of EMT and provides compelling evidence that hK4, in particular, and PSA have a functional role in the progression of prostate cancer through their promotion of tumour cell migration.

Towards inclusion: Provision for diversity in the transition to school

Policies of inclusion challenge the construct of readiness and require schools to prepare for the diversity of children as they transition to school. However, there is limited empirical evidence concerning how this challenge is met. This paper presents two Australian studies that investigate inclusive practices in the transition to school. Study 1 examined the predictors of child outcomes across a sample of 1831 children in 39 schools. The results indicate that both quantity and quality of programme provision influenced outcomes and that programme effects were particularly potent for children with diverse abilities and backgrounds. Study 2 focuses on pedagogy in three of the schools to highlight how this provision can be achieved. Results show that provisions were reactive, that saliency of children’s needs directed school practices and that professional knowledge impacted on measures of quality. Inclusive processes accounting for both child progress and broader family and teaching influences are necessary for improved transition to school.

Inferring phylogenies of evolving sequences without multiple sequence alignment

Alignment-free methods, in which shared properties of sub-sequences (e.g. identity or match length) are extracted and used to compute a distance matrix, have recently been explored for phylogenetic inference. However, the scalability and robustness of these methods to key evolutionary processes remain to be investigated. Here, using simulated sequence sets of various sizes in both nucleotides and amino acids, we systematically assess the accuracy of phylogenetic inference using an alignment-free approach, based on D2 statistics, under different evolutionary scenarios. We find that compared to a multiple sequence alignment approach, D2 methods are more robust against among-site rate heterogeneity, compositional biases, genetic rearrangements and insertions/deletions, but are more sensitive to recent sequence divergence and sequence truncation. Across diverse empirical datasets, the alignment-free methods perform well for sequences sharing low divergence, at greater computation speed. Our findings provide strong evidence for the scalability and the potential use of alignment-free methods in large-scale phylogenomics.

Computational analysis of epigenetic information in human DNA sequences

Over the last few years, investigations of human epigenetic profiles have identified key elements of change to be Histone Modifications, stable and heritable DNA methylation and Chromatin remodeling. These factors determine gene expression levels and characterise conditions leading to disease. In order to extract information embedded in long DNA sequences, data mining and pattern recognition tools are widely used, but efforts have been limited to date with respect to analyzing epigenetic changes, and their role as catalysts in disease onset. Useful insight, however, can be gained by investigation of associated dinucleotide distributions. The focus of this paper is to explore specific dinucleotides frequencies across defined regions within the human genome, and to identify new patterns between epigenetic mechanisms and DNA content. Signal processing methods, including Fourier and Wavelet Transformations, are employed and principal results are reported.

Transition metal layered double hydroxides for energy storage

Various types of layered double hydroxides, a type of clay, were synthesised. They were then electrochemically tested to determine whether the samples would be suitable to store energy as supercapacitors. A manganese aluminium layered double hydroxide was electrochemically tested for the first time and found to have a large capacitance.

Making the transition from pharmacy student to pharmacist: Australian interns' perceptions of professional identity formation

Objectives The experience of transitioning from university to practice influences professional identity formation. It is unclear how this transitioning experience influences pharmacy interns' professional identities. This study aims to examine pharmacy interns' perceptions of their transition from university to the workplace and the influence this had on their pharmacist identities. Methods A qualitative approach using in-depth interviews was adopted for this study. Fifteen interns (community and hospital) from one school of pharmacy in Australia were interviewed. Questions were asked about the nature of their current intern role, their university experiences, how they saw themselves as pharmacists and their perceptions of the transition to practice. Key findings The interns interviewed entered the workplace valuing patient-focused aspects of practice and contributing to patient care. The nature of work meant there were limited opportunities to enact these aspects of their professional identities. The interns were challenged by interactions with patients and doctors, and experienced difficulties reconciling this with their university-derived professional identities. Also, the interns lacked the confidence and strategies to overcome these challenges. Some were exploring alternative ways of being pharmacists. Conclusions This paper argues that graduates' experience of the transition to practice was challenging. This was due to nascent professional identities formed in university and a lack of workplace experiences enabling patient-centred practices. The interns' formation of professional identities was highly responsive to the context of work. To facilitate the development of Australian patient-centred pharmacy practice, supporting professional identity formation should be a focus within pharmacy education.

The transition to palliative care: A critical exploration in the context of metastatic melanoma

This research explored the transition to palliative care process through critical analysis of the experiences of patients diagnosed with metastatic melanoma, family carers and health professionals. The outcomes depict a complex intersection between acute care services and palliative care where the discipline of palliative care struggled to position itself within a highly specialised health system. The findings indicate uncertainty around scopes of practice with ambiguity and tension around the transition to palliative care. The research thus argues for stronger and more coherent partnerships and a critical and interdisciplinary conversation about the positioning of palliative care in the acute care sector.

A smooth transition logit model of the effects of deregulation in the electricity market

This paper introduces the smooth transition logit (STL) model that is designed to detect and model situations in which there is structural change in the behaviour underlying the latent index from which the binary dependent variable is constructed. The maximum likelihood estimators of the parameters of the model are derived along with their asymptotic properties, together with a Lagrange multiplier test of the null hypothesis of linearity in the underlying latent index. The development of the STL model is motivated by the desire to assess the impact of deregulation in the Queensland electricity market and ascertain whether increased competition has resulted in significant changes in the behaviour of the spot price of electricity, specifically with respect to the occurrence of periodic abnormally high prices. The model allows the timing of any change to be endogenously determined and also market participants' behaviour to change gradually over time. The main results provide clear evidence in support of a structural change in the nature of price events, and the endogenously determined timing of the change is consistent with the process of deregulation in Queensland.

Learning experiences for the transition to professional work

A better educated workforce contributes to a more informed and tolerant society with higher economic output, and this is also associated with higher levels of personal health, interpersonal trust and civic and social engagement. Against this backdrop, the role of universities has expanded, as university learning has moved beyond providing an education to preparing students for leadership positions within society. This article examines the effectiveness of final-year learning experiences from the perception of recent graduates. The aim is to improve undergraduate curriculum to facilitate the transition to professional employment. An online quantitative and qualitative survey instrument was developed to investigate graduates’ perceptions of their different learning experiences and assessment types in their senior year. Four hundred and twelve alumni from five universities completed the survey. Our results indicate that graduates value case studies, group work and oral presentations, and that graduates rate lectures and guest lectures from practitioners as the least important in their transition to work. The results validate the use of graduate capability frameworks and mapping the development of the skills over the curriculum. These results are useful for curriculum designers to assist with designing programmes on the transition to professional work.