University of South Australia
Recent publications
Directed acyclic graph (DAG) learning plays a key role in causal discovery and many machine learning tasks. Learning a DAG from high-dimensional data always faces scalability problems. A local-to-global DAG learning approach can be scaled to high-dimensional data, however, existing local-to-global DAG learning algorithms employ either the AND-rule or the OR-rule for constructing a DAG skeleton. Simply using either rule, existing local-to-global methods may learn an inaccurate DAG skeleton, leading to unsatisfactory DAG learning performance. To tackle this problem, in this paper, we propose an A daptive D AG L earning (ADL) algorithm. The novel contribution of ADL is that it can simultaneously and adaptively use the AND-rule and the OR-rule to construct an accurate global DAG skeleton. We conduct extensive experiments on both benchmark and real-world datasets, and the experimental results show that ADL is significantly better than some existing local-to-global and global DAG learning algorithms.
Background : Around 40% of Australian children do not participate in sport. Cost is a major barrier to participation, particularly for children from low socioeconomic backgrounds. This study aimed to evaluate the uptake of a population-level children’s sports subsidy scheme, including sociodemographic differences in uptake. Methods : A state-wide cross-sectional analysis comparing sports voucher claimants (primary school-aged children with a valid Medicare or Australian visa number) from the 2019 financial year with population census data from South Australia. Chi-square was used to examine whether the percentage of eligible children who claimed a voucher differed based on age, sex, socioeconomic status (SES), and geographical remoteness. Subgroup analyses were conducted for the lowest 2 socioeconomic disadvantage deciles, split by gender. Scatterplots were used to compare sports between high and low SES children. Results : A total of 74,668 children claimed sports vouchers (45.5% of eligible children). Children who were relatively younger, female, from low socioeconomic backgrounds, and from major cities were least likely to claim the voucher. The 5 most common sports were Australian rules football (30.2%), netball (13.6%), soccer (13.1%), gymnastics (10.4%), and basketball (5.7%), with the popular sports similar for high and low SES children. Conclusions : Future work is needed to understand how Sports Voucher, and sport participation rates have changed over time, and to improve voucher uptake among girls, city dwellers, and low SES children.
Metasurfaces consisting of planar subwavelength structures with minimal thickness are appealing to emerging technologies such as integrated optics and photonic chips for their small footprint and compatibility with sophisticated planar nanofabrication techniques. However, reduced dimensionality due to the two‐dimensional nature of a metasurface poses challenges to the adaptation of a few useful methods that have found great success with conventional optics in three‐dimensional space. For instance, Bragg diffraction is the foundation of the well‐established technique of phase‐coded multiplexing in volume holography. It relies on interference among the scattered waves from multiple layers across the thickness of a sample. In this work, despite losing the dimension in thickness, a metasurface is devised to experimentally demonstrate phase‐coded multiplexing by replacing free‐space light with a surface wave in its output. The in‐plane interference along the propagation of the surface wave resembles the Bragg diffraction, thus enabling phase‐coded multiplexing in the two‐dimensional design. An example of code‐based all optical routing is also achieved by using a multiplexed metasurface, which could find applications in photonic data processing and communications. This article is protected by copyright. All rights reserved
Copper isotope analysis has emerged as a promising tool for understanding genetic processes in Cu ore deposits. However, applications of this analytical technique to Archean Cu deposits have been extremely limited, even though Archean terranes are among the most economically endowed on Earth. As such, this study presents the first Cu isotope analysis of an Archean Cu deposit, the Mesoarchean Carlow Castle hydrothermal Cu‐Co‐Au deposit. Archean primary Cu sulfide ore samples and Cenozoic supergene Cu ore samples were analyzed. Primary ore samples are isotopically light, with δ⁶⁵Cu values ranging between −0.80 ± 0.02‰ and 0.00 ± 0.007‰, whilst supergene samples are isotopically heavier and range between −0.50 ± 0.01‰ and 0.62 ± 0.005‰. In primary ore samples, a relationship is observed between the Cu isotope signature, ore grade, and alteration assemblage that records the isotopic and physicochemical evolution of the Carlow Castle deposit's hydrothermal ore‐forming system. A mafic igneous source is suggested as a metal source in the Carlow Castle Cu‐Co‐Au deposit. The limited heavy isotopic fractionation of supergene Cu ore samples in this study is interpreted to reflect limited redox cycling of Cu due to in situ oxidative weathering of vein‐hosted Cu sulfides in the overlying Cenozoic supergene system. This differs from previously studied deposits where significant Cu transport and multiple stages of isotopic enrichment are often evident in supergene Cu enrichment layers. The results of this study suggest that Cu isotope analysis could be valuable in understanding genetic processes in hydrothermal Cu deposits, including Archean ore deposits and terranes.
Local-to-global learning approach plays an essential role in Bayesian network (BN) structure learning. Existing local-to-global learning algorithms first construct the skeleton of a DAG (directed acyclic graph) by learning the MB (Markov blanket) or PC (parents and children) of each variable in a data set, then orient edges in the skeleton. However, existing MB or PC learning methods are often computationally expensive especially with a large-sized BN, resulting in inefficient local-to-global learning algorithms. To tackle the problem, in this paper, we link feature selection with local BN structure learning and develop an efficient local-to-global learning approach using filtering feature selection. Specifically, we first analyze the rationale of the well-known Minimum-Redundancy and Maximum-Relevance (MRMR) feature selection approach for learning a PC set of a variable. Based on the analysis, we propose an efficient F2SL (feature selection-based structure learning) approach to local-to-global BN structure learning. The F2SL approach first employs the MRMR approach to learn the skeleton of a DAG, then orients edges in the skeleton. Employing independence tests or score functions for orienting edges, we instantiate the F2SL approach into two new algorithms, F2SL-c (using independence tests) and F2SL-s (using score functions). Compared to the state-of-the-art local-to-global BN learning algorithms, the experiments validated that the proposed algorithms in this paper are more efficient and provide competitive structure learning quality than the compared algorithms.
Importance Ranitidine, the most widely used histamine-2 receptor antagonist (H 2 RA), was withdrawn because of N-nitrosodimethylamine impurity in 2020. Given the worldwide exposure to this drug, the potential risk of cancer development associated with the intake of known carcinogens is an important epidemiological concern. Objective To examine the comparative risk of cancer associated with the use of ranitidine vs other H 2 RAs. Design, Setting, and Participants This new-user active comparator international network cohort study was conducted using 3 health claims and 9 electronic health record databases from the US, the United Kingdom, Germany, Spain, France, South Korea, and Taiwan. Large-scale propensity score (PS) matching was used to minimize confounding of the observed covariates with negative control outcomes. Empirical calibration was performed to account for unobserved confounding. All databases were mapped to a common data model. Database-specific estimates were combined using random-effects meta-analysis. Participants included individuals aged at least 20 years with no history of cancer who used H 2 RAs for more than 30 days from January 1986 to December 2020, with a 1-year washout period. Data were analyzed from April to September 2021. Exposure The main exposure was use of ranitidine vs other H 2 RAs (famotidine, lafutidine, nizatidine, and roxatidine). Main Outcomes and Measures The primary outcome was incidence of any cancer, except nonmelanoma skin cancer. Secondary outcomes included all cancer except thyroid cancer, 16 cancer subtypes, and all-cause mortality. Results Among 1 183 999 individuals in 11 databases, 909 168 individuals (mean age, 56.1 years; 507 316 [55.8%] women) were identified as new users of ranitidine, and 274 831 individuals (mean age, 58.0 years; 145 935 [53.1%] women) were identified as new users of other H 2 RAs. Crude incidence rates of cancer were 14.30 events per 1000 person-years (PYs) in ranitidine users and 15.03 events per 1000 PYs among other H 2 RA users. After PS matching, cancer risk was similar in ranitidine compared with other H 2 RA users (incidence, 15.92 events per 1000 PYs vs 15.65 events per 1000 PYs; calibrated meta-analytic hazard ratio, 1.04; 95% CI, 0.97-1.12). No significant associations were found between ranitidine use and any secondary outcomes after calibration. Conclusions and Relevance In this cohort study, ranitidine use was not associated with an increased risk of cancer compared with the use of other H 2 RAs. Further research is needed on the long-term association of ranitidine with cancer development.
Objective The objective of this scoping review is to describe models of palliative care for under-served populations in high-income countries, defined as adults of culturally and linguistically diverse communities; low socioeconomic status; and/or residing in rural areas. Introduction Models of palliative care are processual, referring to the way palliative care services are delivered as people experience a condition, injury, or event. The aim of these models is to ensure people get the right care, at the right time, by the right team, in the right place. Evidence suggests there is a wide variety of models of palliative care; but what is not known is how these models can vary to meet the needs of under-served populations. Inclusion criteria This scoping review will consider articles that focus on models of palliative care for under-served populations, irrespective of sex, age, or primary diagnosis. Methods MEDLINE (Ovid), Embase (Ovid), PsycINFO (Ovid), Emcare (Ovid), CINAHL (EBSCO), and Scopus will be searched for articles, irrespective of language, published from 2014. Two independent reviewers will screen titles and abstracts, followed by a full-text review of potentially relevant articles. Discrepancies will be reconciled with another reviewer. Two independent reviewers will extract data from included articles using a data extraction tool developed for this review. Results will be tabulated and/or presented diagrammatically, as well as summarized to explicitly address the objective of the review. Review registration Open Science Framework
One of the fundamental challenges in causal inference is to estimate the causal effect of a treatment on its outcome of interest from observational data. However, causal effect estimation often suffers from the impacts of confounding bias caused by unmeasured confounders that affect both the treatment and the outcome. The instrumental variable (IV) approach is a powerful way to eliminate the confounding bias from latent confounders. However, the existing IV-based estimators require a nominated IV, and for a conditional IV (CIV) the corresponding conditioning set too, for causal effect estimation. This limits the application of IV-based estimators. In this paper, by leveraging the advantage of disentangled representation learning, we propose a novel method, named DVAE.CIV, for learning and disentangling the representations of CIV and the representations of its conditioning set for causal effect estimations from data with latent confounders. Extensive experimental results on both synthetic and real-world datasets demonstrate the superiority of the proposed DVAE.CIV method against the existing causal effect estimators.
BACKGROUND: The University of South Australia’s Bachelor of Physiotherapy course, ‘Work Health and Safety (WHS) Practice’, provides students with introductory practical WHS experience. Students undertake 80-hour effort WHS projects for industry, culminating in a report for hosts. OBJECTIVE: To establish types of industry that host WHS undergraduate physiotherapy placements and the nature of activities that students conduct. METHODS: Reports were retrospectively, systematically classified using a descriptive, document content analysis approach. Demographic data were collected: report and student numbers, placement locations and industry types. Selected reports were used as a subset for further analysis with definitions created to classify the nature of placement activities. RESULTS: Most reports were written by a pair of students (88%, n = 269), with placements based in metropolitan YY (91%, n = 284). Various industries hosted students, including healthcare and social assistance (40%, n = 117) and manufacturing (30%, n = 89). Reports primarily included risk management activities as required by WHS legislation (97%, n = 229). CONCLUSION: Physiotherapy student WHS activities maintain close links with industry, a goal of the University of South Australia as a university of enterprise; involving stakeholders (workforce, students, University of South Australia and academics). At an entry-level standard, the student WHS activities align well with some criteria set as key competencies for Australian Occupational Health and Safety practitioners.
High-grade prostatic intraepithelial neoplasia (HGPIN) is a well-characterised precursor lesion in prostate cancer. The term atypical intraductal proliferations (AIP) describes lesions with features that are far too atypical to be considered HGPIN, yet insufficient to be diagnosed as intraductal carcinoma of the prostate (IDCP). Here, a panel of biomarkers was assessed to provide insights into the biological relationship between IDCP, HGPIN, and AIP and their relevance to current clinicopathological recommendations. Tissue samples from 86 patients with prostate cancer were assessed by routine haematoxylin and eosin staining and immunohistochemistry (IHC) with a biomarker panel (Appl1/Sortilin/Syndecan-1) and a PIN4 cocktail (34βE12+P63/P504S). Appl1 strongly labelled atypical secretory cells, effectively visualising intraductal lesions. Sortilin labelling was moderate-to-strong in > 70% of cases, while Syndecan-1 was moderate-to-strong in micropapillary HGPIN/AIP lesions (83% cases) versus flat/tufting HGPIN (≤ 20% cases). Distinct biomarker labelling patterns for atypical intraductal lesions of the prostate were observed, including early atypical changes (flat/tufting HGPIN) and more advanced atypical changes (micropapillary HGPIN/AIP). Furthermore, the biomarker panel may be used as a tool to overcome the diagnostic uncertainty surrounding AIP by supporting a definitive diagnosis of IDCP for such lesions displaying the same biomarker pattern as cribriform IDCP.
As research and practice in corporate governance and risk management evolve, related tools and procedures are also developing in tandem – as is the case with the recent review of the widely adopted and time-tested Three Lines of Defence (TLOD). This new Three Lines Model (TLM) attempts to reflect model criticism and widen the model scope towards integrated governance, naturally setting expectations high. This paper presents the first synopsis of the academic criticisms of TLOD, providing a foundation for analysing the models. In a multi-method approach, the authors triangulate quantitative approaches from the corpus research with qualitative approaches to inquire about their research questions, in what is the first full review of the two original documents. Several converging results from triangulation support this thesis. The findings reveal a revised model that increases complexity yet gives up important parts of the previous model. While addressing key criticisms and adding important clarifications, the logic and simplicity of the old model seem lost – a conclusion that potentially contributes to the current slow adoption of TLM, not least among regulators. In contrast to the positive initial reactions, this paper concludes that a nuanced and critical view of the revamped TLM is necessary. It points out directions for further improvement – as well as those new elements worth preserving, such as the use of newly introduced principles, so that the model can keep its precision and appeal. This paper also inquires what practitioners should do at this stage, especially considering regulations in specific industries, and how the model authors may further develop the three lines. Finally, research limitations are highlighted as well as four research avenues regarding governance and risk identified.
Respiratory syncytial virus (RSV) commonly infects the upper respiratory tract (URT) of humans, manifesting with mild cold or flu-like symptoms. However, in infants and the elderly, severe disease of the lower respiratory tract (LRT) often occurs and can develop into chronic airway disease. A better understanding of how an acute RSV infection transitions to a LRT chronic inflammatory disease is critically important to improve patient care and long-term health outcomes. To model acute and chronic phases of the disease, we infected wild-type C57BL/6 and toll-like receptor 7 knockout (TLR7 KO) mice with RSV and temporally assessed nasal, airway and lung inflammation for up to 42 days post-infection. We show that TLR7 reduced viral titers in the URT during acute infection but promoted pronounced pathogenic and chronic airway inflammation and hyperreactivity in the LRT. This study defines a hitherto unappreciated molecular mechanism of lower respiratory pathogenesis to RSV, highlighting the potential of TLR7 modulation to constrain RSV pathology to the URT.
Line Extensions are among the most common form of product launch in packaged goods markets. As part of this process, brand managers must decide the visual design of the new variant’s packaging. To inform this decision making, this research aims to empirically quantify the efficacy of using colors versus images as signals of product variety on pack. We compare the use of color on 576 packs with perceptions of 1,853 category buyers across three categories in the USA. We find that for 84% of variant types, marketers use common colors to signal variety on pack, while consumers perceive that only 56% of variant types are represented by a particular color. Of greater concern, the colors used in practice and those expected by consumers align in only 16% of cases. By comparison, images are linked to variant types to a significantly greater extent (39% of cases). This suggests images are a stronger and more explicit signal of product variety than color. There are multiple implications arising from this study. It expands scholarly research on the use of colors in product extensions and, at the same time, provides a series of valuable benchmarks for industry practice in the portfolio management domain.
Engaging children with CP (cerebral palsy) in meaningful therapy or exercise can be difficult, despite the merits of the intervention, the potential therapeutic benefits that accompany compliance, and the best intentions of family and rehabilitation specialists to motivate and encourage the child. However, serious games (SG) are highlighted as a resource for engaging children with CP in an immersive and engaging environment. The aim of most SG interventions is to utilise technology to improve attention, engagement, and motivation, which most therapists acknowledge is a challenge when it comes to a rehabilitation programme. This chapter will discuss the design philosophy and evaluation process of a novel SG system in readiness for a home-based trial. In doing so, the chapter addresses both software and hardware accessibility issues simultaneously. A design emphasis for the system as a whole was the incorporation of sensory (haptic) feedback into both the games and the controller to augment the potential therapeutic effects of play.
Inconel 718 is a superalloy known for its excellent mechanical, corrosion, and creep resistance, even at high temperatures up to 700 °C. It is a valuable material that accounts for almost 50% of all superalloys used worldwide. However, its outstanding properties also make it a difficult-to-cut material that generates high heat at the chip tool interface, putting a strain on cutting tools. Although ceramic tools are a suitable option, cemented carbide tools, especially those in the "S" grades, can also be used, albeit with low-cutting conditions. To make cemented carbide tools viable for such applications, a lubricating-cooling medium is necessary. The most common method is the application of cutting fluids in abundance, also known as CFA. However, CFA strongly affects sustainable processes, creating economic, social, and environmental problems. Various research works have been developed worldwide to address this issue to replace or eliminate CFA. This work proposes a novel method that uses internally cooled tools (ICT). Some advantages of this method is that it holds significant appeal from the environmental sustainability perspective, as it eliminates any release of fluids into the atmosphere preventing its improper disposal, as the coolant, operates in a closed-loop cycle. Another aspect that enhances the attractiveness of ICTs is their low toxicity for operators, as the coolant doesn't come into direct contact with them, thereby avoiding any risk of workplace contamination.The method was developed and tested using cemented carbide inserts with internal galleries through which coolant (in this case, water) can circulate and cool the tool. The cooling fluid, responsible for cooling the tool, operates in a closed-loop cycle. Another aspect that enhances the attractiveness of ICTs (Internal Cooling Technologies) is their low toxicity for operators, as the coolant doesn't come into direct contact with them, thereby avoiding any risk of workplace contamination.Tool life tests were carried out on turning Inconel 718 with this system, followed by analyses of the wear mechanisms. The input variables were the cutting atmospheres, in three levels (ICT, CFA, and dry machining – DM) and the tool's coating, in two levels (TiNAl and Alnova +). The cutting speed (v_c=45 m/min), feed rate (f=0.103 mm/rev) and depth of cut (doc) (a_p=0.5 mm) were kept constant in a finishing condition. For statistical reliability, the tests were replicated twice, totaling 18 tests overall. After the tests, the tools were analyzed using scanning electron microscopy (SEM) equipped with energy-dispersive spectroscopy (EDS) to determine the wear mechanisms. Overall, the results showed that Alnova + performed better than TiAlN, and ICT gave the highest tool life when using TiAlN coating tools. However, when using Alnova + coating, the best results were achieved with CFA. Abrasion, adhesion, oxidation, and diffusion wear mechanisms were observed regardless of the tool coating or atmosphere conditions used. However, Alnova + tended to show smoother and more uniform wear, with a predominance of flank and crater wear.
Objective To investigate the impact of the COVID-19 pandemic on clinical supervision practices of health care workers in health care settings in one Australian state. Method A bespoke survey was developed and administered online using Qualtrics™. The survey consisted of Likert scale and closed questions, with options for free text comments. Numerical data were analysed descriptively and using Chi-Square tests. Textual data were analysed through content analysis. Results Of the 178 survey respondents, 42% were from allied health disciplines, 39% from nursing and midwifery, and 19% from medicine. The type and mode (i.e., face-to-face, telesupervision) of clinical supervision prior to the pandemic and at the time of survey completion (i.e., July–August 2021) were similar. Eighteen percent of respondents had a change in supervision arrangements but only 5% had a change in supervisor. For the 37% who changed roles due to COVID-19, 81% felt their current supervisor was still able to support them, 69% were still having their supervisory needs met. Analyses of textual data resulted in the development of two categories: Supervision deteriorating, and some clinical supervision functions (i.e., formative and restorative) being more impacted than others (i.e., normative). Conclusion There were substantial disruptions to several parameters of clinical supervision due to COVID-19, that may pose a threat to high quality supervision. Health care workers reported pandemic-induced stress and mental health challenges that were not always addressed by effective restorative supervision practices.
We have previously reported promising in vivo activity of the first-generation 2-aminopyramidine robenidine analogue NCL195 against Gram-positive bacteria (GPB) when administered via the systemic route. In this study, we examined the efficacy of oral treatment with NCL195 (± low-dose colistin) in comparison to oral moxifloxacin in bioluminescent Staphylococcus aureus and Escherichia coli peritonitis-sepsis models. Four oral doses of 50 mg/kg NCL195, commencing immediately post-infection, were administered at 4 h intervals in the S. aureus peritonitis-sepsis model. We used a combination of four oral doses of 50 mg/kg NCL195 and four intraperitoneal doses of colistin at 0.125 mg/kg, 0.25 mg/kg, or 0.5 mg/kg in the E. coli peritonitis-sepsis model. Subsequently, the dose rates of four intraperitoneal doses of colistin were increased to 0.5 mg/kg, 1 mg/kg, or 2 mg/kg at 4 h intervals to treat a colistin-resistant E. coli infection. In the S. aureus infection model, oral treatment of mice with NCL195 resulted in significantly reduced S. aureus infection loads (P < 0.01) and longer survival times (P < 0.001) than vehicle-only treated mice. In the E. coli infection model, co-administration of NCL195 and graded doses of colistin resulted in a dose-dependent significant reduction in colistin-susceptible (P < 0.01) or colistin-resistant (P < 0.05) E. coli loads compared to treatment with colistin alone at similar concentrations. Our results confirm that NCL195 is a potential candidate for further preclinical development as a specific treatment for multidrug-resistant infections, either as a stand-alone antibiotic for GPB or in combination with sub-inhibitory concentrations of colistin for Gram-negative bacteria.
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Alistair McCulloch
  • Research & Innovation Services
Lorimer Moseley
  • IIMPACT in Health
Kristin V Carson-Chahhoud
  • School of Health Sciences
Adelaide, Australia