Volume estimation from multiplanar 2D ultrasound images using a remote electromagnetic position and orientation sensor

A system is described for calculating volume from a sequence of multiplanar 2D ultrasound images. Ultrasound images are captured using a video digitising card (Hauppauge Win/TV card) installed in a personal computer, and regions of interest transformed into 3D space using position and orientation data obtained from an electromagnetic device (Polbemus, Fastrak). The accuracy of the system was assessed by scanning 10 water filled balloons (13-141 ml), 10 kidneys (147  200 ml) and 16 fetal livers (8  37 ml) in water using an Acuson 128XP/10 (5 MHz curvilinear probe). Volume was calculated using the ellipsoid, planimetry, tetrahedral and ray tracing methods and compared with the actual volume measured by weighing (balloons) and water displacement (kidneys and livers). The mean percentage error for the ray tracing method was 0.9 ± 2.4%, 2.7 ± 2.3%, 6.6 ± 5.4% for balloons, kidneys and livers, respectively. So far the system has been used clinically to scan fetal livers and lungs, neonate brain ventricles and adult prostate glands.

Prediction and measurement of multiuser MIMO-OFDM channel in rural Australia

Commonwealth Scientific and Industrial Research Organization (CSIRO) has recently conducted a technology demonstration of a novel fixed wireless broadband access system in rural Australia. The system is based on multi user multiple-input multiple-output orthogonal frequency division multiplexing (MU-MIMO-OFDM). It demonstrated an uplink of six simultaneous users with distances ranging from 10 m to 8.5 km from a central tower, achieving 20 bits s/Hz spectrum efficiency. This paper reports on the analysis of channel capacity and bit error probability simulation based on the measured MUMIMO-OFDM channels obtained during the demonstration, and their comparison with the results based on channels simulated by a novel geometric optics based channel model suitable for MU-MIMO OFDM in rural areas. Despite its simplicity, the model was found to predict channel capacity and bit error rate probability accurately for a typical MU-MIMO-OFDM deployment scenario.

The rest flies down the wind : complexities of late style in the work of Christina Stead

Examining the late style of a writer is like skirting around quicksand. End-of-career reflection can subvert long standing critical accounts; revisionist publishing histories or newly minted archival work can do likewise. And, as Nancy J. Troy suggests, an artist’s last thoughts are rarely planned as such (15). In the case of Christina Stead any consideration of late style is made more difficult because, chronologically speaking, her ‘late’ works were written some 20 years before her death in 1983. Thus chronology can be deceptive, as Nicholas Delbanco points out in Lastingness: The Art of Old Age. Stead’s last novel, I’m Dying Laughing The Humourist, was completed, at least in rough draft form in 1966, when Stead was 64, but friends and readers suggested many changes. The book was published posthumously in 1986. Stead’s work is receiving increasing critical attention so a discussion of her ‘late style’ is important, particularly given that her fiction seems to refuse so many attempts at category-making. This perspective reveals two interesting aspects of her late work: first her consistent engagement with the problems of age for women, and in particular women writers, and second, the consequence of a life-long attention to the representation of dialogic sound in her novels, a preoccupation that results in what can be termed an aural signature. My discussion refers to Edward Said’s and Nicholas Delbanco’s ideas about late style by way of a focus on selective biographical issues and Stead’s engagement with radical politics before moving to an examination of what can be called an aural signature in several novels. Her fiction demonstrates one of the agreed markers of late style: she was constantly looking forward and looking back through innovation in form and content.

Reliability of clinical measurement for assessing spinal fusion: An experimental sheep study

Study Design. A sheep study designed to compare the accuracy of static radiographs, dynamic radiographs, and computed tomographic (CT) scans for the assessment of thoracolumbar facet joint fusion as determined by micro-CT scanning. Objective. To determine the accuracy and reliability of conventional imaging techniques in identifying the status of thoracolumbar (T13-L1) facet joint fusion in a sheep model. Summary of Background Data. Plain radiographs are commonly used to determine the integrity of surgical arthrodesis of the thoracolumbar spine. Many previous studies of fusion success have relied solely on postoperative assessment of plain radiographs, a technique lacking sensitivity for pseudarthrosis. CT may be a more reliable technique, but is less well characterized. Methods. Eleven adult sheep were randomized to either attempted arthrodesis using autogenous bone graft and internal fixation (n = 3) or intentional pseudarthrosis (IP) using oxidized cellulose and internal fixation (n = 8). After 6 months, facet joint fusion was assessed by independent observers, using (1) plain static radiography alone, (2) additional dynamic radiographs, and (3) additional reconstructed spiral CT imaging. These assessments were correlated with high-resolution micro-CT imaging to predict the utility of the conventional imaging techniques in the estimation of fusion success. Results. The capacity of plain radiography alone to correctly predict fusion or pseudarthrosis was 43% and was not improved using plain radiography and dynamic radiography with also a 43% accuracy. Adding assessment by reformatted CT imaging to the plain radiography techniques increased the capacity to predict fusion outcome to 86% correctly. The sensitivity, specificity, and accuracy of static radiography were 0.33, 0.55, and 0.43, respectively, those of dynamic radiography were 0.46, 0.40, and 0.43, respectively, and those of radiography plus CT were 0.88, 0.85, and 0.86, respectively. Conclusion. CT-based evaluation correlated most closely with high-resolution micro-CT imaging. Neither plain static nor dynamic radiographs were able to predict fusion outcome accurately. © 2012 Lippincott Williams & Wilkins.

A comparative study of the number and mass of fine particles emitted with diesel fuel and marine gas oil (MGO)

The current investigation reports on diesel particulate matter emissions, with special interest in fine particles from the combustion of two base fuels. The base fuels selected were diesel fuel and marine gas oil (MGO). The experiments were conducted with a four-stroke, six-cylinder, direct injection diesel engine. The results showed that the fine particle number emissions measured by both SMPS and ELPI were higher with MGO compared to diesel fuel. It was observed that the fine particle number emissions with the two base fuels were quantitatively different but qualitatively similar. The gravimetric (mass basis) measurement also showed higher total particulate matter (TPM) emissions with the MGO. The smoke emissions, which were part of TPM, were also higher for the MGO. No significant changes in the mass flow rate of fuel and the brake-specific fuel consumption (BSFC) were observed between the two base fuels.

The four principles: Can they be measured and do they predict ethical decision making?

Background The four principles of Beauchamp and Childress - autonomy, non-maleficence, beneficence and justice - have been extremely influential in the field of medical ethics, and are fundamental for understanding the current approach to ethical assessment in health care. This study tests whether these principles can be quantitatively measured on an individual level, and then subsequently if they are used in the decision making process when individuals are faced with ethical dilemmas. Methods The Analytic Hierarchy Process was used as a tool for the measurement of the principles. Four scenarios, which involved conflicts between the medical ethical principles, were presented to participants and they made judgments about the ethicality of the action in the scenario, and their intentions to act in the same manner if they were in the situation. Results Individual preferences for these medical ethical principles can be measured using the Analytic Hierarchy Process. This technique provides a useful tool in which to highlight individual medical ethical values. On average individuals have a significant preference for non-maleficence over the other principles, however, and perhaps counter-intuitively, this preference does not seem to relate to applied ethical judgements in specific ethical dilemmas. Conclusions People state they value these medical ethical principles but they do not actually seem to use them directly in the decision making process. The reasons for this are explained through the lack of a behavioural model to account for the relevant situational factors not captured by the principles. The limitations of the principles in predicting ethical decision making are discussed.

Validity and reliability of instruments designed to measure factors influencing the overuse of antibiotics

Background: Antibiotic overuse is a global public health issue that is influenced by several factors. The degree and prevalence of antibiotic overuse is difficult to measure directly. A more practical approach, such as the use of a psycho-social measurement instrument, might allow for the observation and assessment of patterns of antibiotic use. Study objective: The aim of this paper is to review the nature, validity, and reliability of measurement scales designed to measure factors associated with antibiotic misuse/overuse. Design: This study is descriptive and includes a systematic integration of the measurement scales used in the literature to measure factors associated with antibiotic misuse/overuse. The review included 70 international scientific publications from 1992 to 2010. Main results: Studies have presented scales to measure antibiotic misuse. However, the workup of these instruments is often not mentioned, or the scales are used with only early-phase validation, such as content or face validity. Other studies have discussed the reliability of these scales. However, the full validation process has not been discussed in any of the reviewed measurement scales. Conclusion: A reliable, fully validated measurement scale must be developed to assess the factors associated with the overuse of antibiotics. Identifying these factors will help to minimize the misuse of antibiotics.

Getting stuck in together : improving work integrated learning from an Australian institution and faculty perspective

According to a recent report Australian higher education is not in crisis. However, we could be doing it better. The report Mapping Australian Higher Education (Norton, 2012) highlights comparative weaknesses such as levels f student engagement; interactions between students and academic staff; and academic staff preferences for research over teaching. The report points out that despite these concerns most graduates continue to get good, well-paid jobs, student satisfaction is improving, and levels of public confidence in Australian higher education are high. It also stresses that ‘the promise of higher education is that it provides adaptable cognitive skills, not that it always provides the job specific skills graduates will need in their future employment’ (Norton, 2012, p.58). This is worth keeping in mind as we contribute to the significant growth in curriculum initiatives aimed at preparing graduates for the world of work. Work Integrated Learning (WIL) is not a new concept but there is increased pressure on higher education globally to address graduate employability skills. The sector is under pressure in an increasingly competitive environment to demonstrate the relevance of courses, accountability and effective use of public funds (Peach & Gamble, 2011). In the Australian context this also means responding to the skills shortage in areas such as engineering, health, construction and business (DEEWR, 2010). This paper provides a brief overview of collaborative efforts over several years to improve the activity of WIL at the Queensland University of Technology (QUT). These efforts have resulted in changes to curriculum, pedagogy, systems and processes, and the initiation of local, regional, national, and international networks. The willingness of students, staff, and industry partners to ‘get stuck in’ and try new approaches in these different contexts can be understood as a form of boundary spanning. That is, the development of the capability to mediate between different forms of expertise and the demands of different contexts in order to nurture student learning and improve the outcomes of higher education through WIL (Peach, Cates, Ilg, Jones, Lechleiter, 2011).

Challenges of Measuring Learning Outcomes for Property Students Engaged in Work Integrated Learning

Work integrated learning (WIL) or professional practice units are recognised as providing learning experiences that help students make successful transitions to professional practice. These units require students to engage in learning in the workplace; to reflect on this learning; and to integrate it with learning at university. However, an analysis of a recent cohort of property economics students at a large urban university provides evidence that there is great variation in work based learning experiences undertaken and that this impacts on students’capacity to respond to assessment tasks which involve critiquing these experiences in the form of reflective reports. This paper highlights the need to recognise the diversity of work based experiences; the impact this has on learning outcomes; and to find more effective and equitable ways of measuring these outcomes. The paper briefly discusses assessing learning outcomes in WIL and then describes the model of WIL in the Faculty of Built Environment and Engineering at the Queensland University of Technology (QUT). The paper elaborates on the diversity of students’ experiences and backgrounds including variations in the length of work experience, placement opportunities and conditions of employment.For example, the analysis shows that students with limited work experience often have difficulty critiquing this work experience and producing high level reflective reports. On the other hand students with extensive, discipline relevant work experience can be frustrated by assessment requirements that do not take their experience into account. Added to this the Global Financial Crisis (GFC) has restricted both part time and full time placement opportunities for some students. These factors affect students’ capacity to a) secure a relevant work experience, b) reflect critically on the work experiences and c) appreciate the impact the overall experience can have on their learning outcomes and future professional opportunities. Our investigation highlights some of the challenges faced in implementing effective and equitable approaches across diverse student cohorts. We suggest that increased flexibility in assessment requirements and increased feedback from industry may help address these challenges.

Benefits of publicly available data

The National Morbidity, Mortality, and Air Pollution Study (NMMAPS) was designed to examine the health effects of air pollution in the United States. The primary question was whether particulate matter was responsible for the associations between air pollution and daily mortality. Secondary questions concerned measurement error in air pollution and mortality displacement.1 Since then, NMMAPS has been used to answer many important questions in environmental epidemiology...

Choosing work and care : four Australian women negotiating return to paid work in the first year of motherhood

Australian women make decisions about return to paid work and care for their child within a policy environment that presents mixed messages about maternal employment and child care standards. Against this background an investigation of first-time mothers’ decision-making about workforce participation and child care was undertaken. Four women were studied from pregnancy through the first postnatal year using interview and diary methods. Inductive analyses identified three themes, all focused on dimensions of family security: financial security relating to family income, emotional security relating to child care quality, and pragmatic security relating to child care access. The current policy changes that aim to increase child care quality standards in Australia present a positive step toward alleviating family insecurities but are insufficient to alleviate the evidently high levels of tension between workforce participation and family life experienced by women transitioning back into the workforce in Australia.

Monte Carlo modeling of a 4 mm conical collimator for a Novalis Tx Linear Accelerator

The work presented in this poster outlines the steps taken to model a 4 mm conical collimator (BrainLab, Germany) on a Novalis Tx linear accelerator (Varian, Palo Alto, USA) capable of producing a 6MV photon beam for treatment of Stereotactic Radiosurgery (SRS) patients. The verification of this model was performed by measurements in liquid water and in virtual water. The measurements involved scanning depth dose and profiles in a water tank plus measurement of output factors in virtual water using Gafchromic® EBT3 film.

Navigational traffic conflict technique: a proactive approach to quantitative measurement of collision risks in port waters

Navigational safety analysis relying on collision statistics is often hampered because of low number of observations. A promising alternative approach that overcomes this problem is proposed in this paper. By analyzing critical vessel interactions this approach proactively measures collision risk in port waters. The proposed method is illustrated for quantitative measurement of collision risks in Singapore port fairways, and validated by examining correlations between the measured risks with those perceived by pilots. This method is an ethically appealing alternative to the collision-based analysis for fast, reliable and effective safety assessment, thus possesses great potential for managing collision risks in port waters.

Assessing for work integrated learning experiences : a pre-service teacher perspective

A critical aspect of the debate about work integrated learning in the university context is the blurring of boundaries and responsibilities in terms of student learning. In an Australian pre-service teacher education program this blurring of boundaries is apparent in stakeholder tensions about the nature and role of assessment during the practicum. In the study reported in this paper, students responded positively to the content of assessment tasks but maintained that their efforts to implement the associated planning in the workplace were stymied because of disparate understandings between university and school staff about the purpose of the task.