The PhD experience at the Australian National University

This paper presents an impression of the PhD-student experience at the Australian National University gained during my term as Dean of the Graduate School from 1990 to 1998. It is based mainly on comments made by individual students in 150 confidential "exit interviews" conducted from 1994 to 1998 inclusive, and, to a lesser extent, on matters raised in approximately 100 meetings requested by students throughout my term. Other activities arising from the role of Dean have also helped to mould my views,including, for example, 8 years as Chair of the University's Graduate Degrees Committee. The picture which emerges is strongly positive. It is clear that for most students the PhD experience at the ANU has been satisfying, productive, stimulating and enjoyable. Supervision is by far the matter of greatest concern to students. It appears that the overall quality of supervision provided for PhD students at the ANU is good, but there is variability, and 'horror stories'are sometimes heard. Student concerns include slow or superficial reading of written material by supervisors, lack of regular contact with supervisors, lack of supervisory expertise in the thesis topic, problems arising from the limitation of scholarship duration to three and a half years, gender-related matters, and plagiarism

Influence of Longitudinal Position on the Evolution of Steady-State Signal in Cardiac Cine Balanced Steady-State Free Precession Imaging

Background: Emerging quantitative cardiac magnetic resonance imaging (CMRI) techniques use cine balanced steady-state free precession (bSSFP) to measure myocardial signal intensity and probe underlying physiological parameters. This correlation assumes that steady-state is maintained uniformly throughout the heart in space and time. Purpose: To determine the effects of longitudinal cardiac motion and initial slice position on signal deviation in cine bSSFP imaging by comparing two-dimensional (2D) and three-dimensional (3D) acquisitions. Material and Methods: Nine healthy volunteers completed cardiac MRI on a 1.5-T scanner. Short axis images were taken at six slice locations using both 2D and 3D cine bSSFP. 3D acquisitions spanned two slices above and below selected slice locations. Changes in myocardial signal intensity were measured across the cardiac cycle and compared to longitudinal shortening. Results: For 2D cine bSSFP, 46% ± 9% of all frames and 84% ± 13% of end-diastolic frames remained within 10% of initial signal intensity. For 3D cine bSSFP the proportions increased to 87% ± 8% and 97% ± 5%. There was no correlation between longitudinal shortening and peak changes in myocardial signal. The initial slice position significantly impacted peak changes in signal intensity for 2D sequences (P \u3c 0.001). Conclusion: The initial longitudinal slice location significantly impacts the magnitude of deviation from steady-state in 2D cine bSSFP that is only restored at the center of a 3D excitation volume. During diastole, a transient steady-state is established similar to that achieved with 3D cine bSSFP regardless of slice location

Effects of D-amino acid oxidase inhibition on memory performance and long-term potentiation in vivo

N-methyl-d-aspartate receptor (NMDAR) activation can initiate changes in synaptic strength, evident as long-term potentiation (LTP), and is a key molecular correlate of memory formation. Inhibition of d-amino acid oxidase (DAAO) may increase NMDAR activity by regulating d-serine concentrations, but which neuronal and behavioral effects are influenced by DAAO inhibition remain elusive. In anesthetized rats, extracellular field excitatory postsynaptic potentials (fEPSPs) were recorded before and after a theta frequency burst stimulation (TBS) of the Schaffer collateral pathway of the CA1 region in the hippocampus. Memory performance was assessed after training with tests of contextual fear conditioning (FC, mice) and novel object recognition (NOR, rats). Oral administration of 3, 10, and 30 mg/kg 4H-furo[3,2-b]pyrrole-5-carboxylic acid (SUN) produced dose-related and steady increases of cerebellum d-serine in rats and mice, indicative of lasting inhibition of central DAAO. SUN administered 2 h prior to training improved contextual fear conditioning in mice and novel object recognition memory in rats when tested 24 h after training. In anesthetized rats, LTP was established proportional to the number of TBS trains. d-cycloserine (DCS) was used to identify a submaximal level of LTP (5× TBS) that responded to NMDA receptor activation; SUN administered at 10 mg/kg 3–4 h prior to testing similarly increased in vivo LTP levels compared to vehicle control animals. Interestingly, in vivo administration of DCS also increased brain d-serine concentrations. These results indicate that DAAO inhibition increased NMDAR-related synaptic plasticity during phases of post training memory consolidation to improve memory performance in hippocampal-dependent behavioral tests

Exploring unwarranted clinical variation: The attitudes of midwives and obstetric medical staff regarding induction of labour and planned caesarean section

Background: Unexplained clinical variation is a major issue in planned birth i.e. induction of labour and planned caesarean section. Aim: To map attitudes and knowledge of maternity care professionals regarding indications for planned birth, and assess inter-professional (midwifery versus medical) and intra-professional variation. Methods: A custom-created survey of medical and midwifery staff at eight Sydney hospitals. Staff were asked to rate their level of agreement with 45 “evidence-based” statements regarding caesareans and inductions on a five-point Likert scale. Responses were grouped by profession, and comparisons made of inter- and intra-professional responses. Findings: Total 275 respondents, 78% midwifery and 21% medical. Considerable inter- and intra-professional variation was noted, with midwives generally less likely to consider any of the planned birth indications “valid” compared to medical staff. Indications for induction with most variation in midwifery responses included maternal characteristics (age≥40, obesity, ethnicity) and fetal macrosomia; and for medical personnel in-vitro fertilisation, maternal request, and routine induction at 39 weeks gestation. Indications for caesarean with most variation in midwifery responses included previous lower segment caesarean section, previous shoulder dystocia, and uncomplicated breech; and for medical personnel uncomplicated dichorionic twins. Indications with most inter-professional variation were induction at 41+ weeks versus 42+ weeks and cesarean for previous lower segment caesarean section. Discussion: Both inter- and intra-professional variation in what were considered valid indications reflected inconsistency in underlying evidence and/or guidelines. Conclusion: Greater focus on interdisciplinary education and consensus, as well as on shared decision-making with women, may be helpful in resolving these tensions

Two-stage Decompositions for the Analysis of Functional Connectivity for fMRI With Application to Alzheimer\u27s Disease Risk

Functional connectivity is the study of correlations in measured neurophysiological signals. Altered functional connectivity has been shown to be associated with numerous diseases including Alzheimer\u27s disease and mild cognitive impairment. In this manuscript we use a two-stage application of the singular value decomposition to obtain data driven population-level measures of functional connectivity in functional magnetic resonance imaging (fMRI). The method is computationally simple and amenable to high dimensional fMRI data with large numbers of subjects. Simulation studies suggest the ability of the decomposition methods to recover population brain networks and their associated loadings. We further demonstrate the utility of these decompositions in a case-control functional logistic regression model. The method is applied to a novel fMRI study of Alzheimer\u27s disease risk under a verbal paired associates task. We found empirical evidence of alternative connectivity in clinically asymptomatic at-risk subjects when compared to controls. The relevant brain network loads primarily on the temporal lobe and overlaps significantly with the olfactory areas and temporal poles