ANU Research Publications

Permanent URI for this collectionhttps://hdl.handle.net/1885/26

The Australian National University's Research Publications collection is an online location for collecting, preserving and disseminating the scholarly output of the University. This service allows members of the University to share their research with the wider community. ANU Open Research accepts journal articles, conference papers, book chapters, working or technical papers and other forms of scholarly communication.

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Now showing 1 - 20 of 121506

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A search for Wigner cusps and resonances in positron scattering by atoms and molecules
(2012) Caradonna, P.; Makochekanwa, C.; Jones, A.; MacHacek, J. R.; Sullivan, J. P.; Buckman, S. J.
Detailed elastic cross-section measurements in the vicinity of the positronium (Ps) formation threshold for He, Ne, Ar, Kr and Xe show a cusp-like feature, made visible by a small and localised depression of between (2 to 15%) of the cross-section value. Other near-threshold structures such as scattering resonances have been demonstrated in close-coupling and convergent-close- coupling calculations for helium. This investigation is undertaken to explicitly search for the presence or otherwise of scattering structures using a high efficiency (∼ 1 % statistical uncertainty) and high resolution (< 70 meV) transmission based apparatus.
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Local and dimension adaptive stochastic collocation for uncertainty quantification
(2013) Jakeman, John D.; Roberts, Stephen G.
In this paper we present a stochastic collocation method for quantifying uncertainty in models with large numbers of uncertain inputs and non-smooth input-output maps. The proposed algorithm combines the strengths of dimension adaptivity and hierarchical surplus guided local adaptivity to facilitate computationally efficient approximation of models with bifurcations/ discontinuties in high-dimensional input spaces. A comparison is made against two existing stochastic collocation methods and found, in the cases tested, to significantly reduce the number of model evaluations needed to construct an accurate surrogate model. The proposed method is then used to quantify uncertainty in a model of flow through porous media with an unknown permeability field. A Karhunen-Loève expansion is used to parameterize the uncertainty and the resulting mean and variance in the speed of the fluid and the time dependent saturation front are computed.
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Malware in spam email
(2020-09-22) Broadhurst, Roderic; Trivedi, Harshit
A 10 percent sample of a 2016 dataset of 25.76 million spam emails provided by the Australian Communications and Media Authority's Spam Intelligence Database was scanned for malware using the VirusTotal Malware database. Nearly one in 10 (9.9% or 255,222) emails were identified as malware compromised and, similarly, 9.9 percent were identified as inactive. Of the compromised URL sites, nearly one-third (31.8% or 81,176) could be further classified as phishing (58.4%) or trojan-compromised URLs (40.6%) or dedicated malicious websites (1%). All 115,025 unique file attachments found in the entire sample (0.5% of all spam) were also scanned and 31.4 percent (36,405) were compromised with various forms of malware. The majority of compromised attachments were found in images (55.6%), followed by PDFs (15.0%) and binary files (10.0%). Various trojans and ransomware were the most common malware, and these and others identified in the sample are described.
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A comparison of some basic monetary policy regimes for open economies
(1993) Henderson, Dale W.; McKibbin, Warwick J.
Monetary policy regime combinations are compared for symmetric and asymmetric temporary shocks to money demand, goods demand, and productivity. In every region, the interest-rate instrument is either kept constant or changed to eliminate (full instrument adjustment) or reduce (partial instrument adjustment) the gap between actual and desired values for an intermediate target: the money supply, nominal income, or output plus inflation. Nominal wage persistence may be absent (Contract hypothesis) or present (Phillips hypothesis). There are analytical and simulation results from a two-region workhorse model and simulation results from the McKibbin-Sachs Global model. The ranking of regime combinations depends not only on the ultimate target and the source of shocks but also on the degrees of instrument adjustment and wage persistence.
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Anti-tuberculous therapy and acute liver failure
(1995-03-04) Mitchell, Imogen; Wendon, Julia; Fitt, Sarah; Williams, Roger
The incidence of tuberculosis has been increasing since 1987, exposing a greater number of patients to the risks of three potentially hepatotoxic drugs, isoniazid, rifampicin, and pyrazinamide. Awareness of potentially severe drug hepatotoxic reactions is vital because fulminant hepatic failure is a devastating and often fatal condition without liver transplantation. We report four cases of fulminant hepatic failure caused by rifampicin, isoniazid, or both. These cases highlight the need for stricter adherence to and review of current guidelines on liver function tests after starting anti-tuberculous therapies.
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A star in a 15.2-year orbit around the supermassive black hole at the centre of the Milky Way
(2002-10-01) Schödel, R.; Ott, T.; Genzel, R.; Hofmann, R.; Lehnert, M.; Eckart, A.; Mouawad, N.; Alexander, T.; Reid, M. J.; Lenzen, R.; Hartung, M.; Lacombe, F.; Rouan, D.; Gendron, E.; Rousset, G.; Lagrange, A. -M.; Brandner, W.; Ageorges, N.; Lidman, C.; Moorwood, A. F. M.; Spyromilio, J.; Hubin, N.; Menten, K. M.
Many galaxies are thought to have supermassive black holes at their centres-more than a million times the mass of the Sun. Measurements of stellar velocities and the discovery of variable X-ray emission have provided strong evidence in favour of such a black hole at the centre of the Milky Way, but have hitherto been unable to rule out conclusively the presence of alternative concentrations of mass. Here we report ten years of high-resolution astrometric imaging that allows us to trace two-thirds of the orbit of the star currently closest to the compact radio source (and massive black-hole candidate) Sagittarius A*. The observations, which include both pericentre and apocentre passages, show that the star is on a bound, highly elliptical keplerian orbit around Sgr A*, with an orbital period of 15.2 years and a pericentre distance of only 17 light hours. The orbit with the best fit to the observations requires a central point mass of (3.7 +/- 1.5) × 106 solar masses (M). The data no longer allow for a central mass composed of a dense cluster of dark stellar objects or a ball of massive, degenerate fermions.
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Rayleigh-wave attenuation across the conterminous United States in the microseism frequency band
(2021-05-12) Magrini, Fabrizio; Boschi, Lapo; Gualtieri, Lucia; Lekic, Vedran; Cammarano, Fabio
Mapping variations in the attenuation of seismic energy is important for understanding dissipative mechanisms in the lithosphere, and for modeling ground shaking associated with earthquakes. We cross-correlate ambient seismic signal recorded across the EarthScope Transportable Array in the 3-15 s period range. We apply to the resulting cross correlations a new method to estimate lateral variations in Rayleigh-wave attenuation, as a function of period, beneath North America. Between 3 and 6 s, our maps are dominated by a strong eastward decrease in attenuation. This pattern vanishes at longer periods, confirming early observations based on regional earthquakes. Attenuation maps and phase-velocity maps are anti-correlated at periods between 3 and 6 s, but the anti-correlation is also largely lost at longer periods. This corresponds to the attenuation coefficient decreasing with period more rapidly in the west than in the east, while the change in phase velocity with period is more uniform across the continent. Our results point to a transition in the properties of upper-crustal materials with depth, probably related to the closure of fluid-filled cracks and pores, and imply that measures of attenuation from seismic noise carry significant information on crustal rheology.
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Beliefs and denials about climate change
(2012-12-01) Leviston, Zoe; Walker, Iain
Despite the scientific evidence and consensus surrounding human-induced climate change, significant skepticism persists within the community, political circles, and some academic spheres. Some suggest that skepticism has shifted from outright denial that the climate is changing to a denial that humans contribute to climate change. We suggest that denial takes numerous forms and investigate this proposition using data from an Australian national survey (2010; n=5,036). Although most Australians believe that climate change is occurring, they are split on their stated beliefs about the causes of climate change. The view that climate change is caused solely by natural fluctuations in Earth's temperatures appears to be widely held, and those who hold this view differ both from those who reject climate change outright and those who accept anthropogenic climate change. We examine correlates of beliefs about climate change and show that beliefs are significantly related to levels of proenvironmental behavior, political orientation, locus of responsibility, cognitive evaluations, affective responses, and perceived moral duty to act. The results suggest that in the future it will be important to account for more nuanced forms of climate change denial, including denial of responsibility and moral duty among those with the "correct" stated beliefs, in overcoming the gap between beliefs, attitudes, and behaviors applicable to different kinds of "believers" and "deniers."
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The effect of polyterpenol thin film surfaces on bacterial viability and adhesion
(2011) Bazaka, Kateryna; Jacob, Mohan V.; Truong, Vi Khanh; Crawford, Russell J.; Ivanova, Elena P.
The nanometer scale surface topography of a solid substrate is known to influence the extent of bacterial attachment and their subsequent proliferation to form biofilms. As an extension of our previous work on the development of a novel organic polymer coating for the prevention of growth of medically significant bacteria on three-dimensional solid surfaces, this study examines the effect of surface coating on the adhesion and proliferation tendencies of Staphylococcus aureus and compares to those previously investigated tendencies of Pseudomonas aeruginosa on similar coatings. Radio frequency plasma enhanced chemical vapor deposition was used to coat the surface of the substrate with thin film of terpinen-4-ol, a constituent of tea-tree oil known to inhibit the growth of a broad range of bacteria. The presence of the coating decreased the substrate surface roughness from approximately 2.1 nm to 0.4 nm. Similar to P. aeruginosa, S. aureus presented notably different patterns of attachment in response to the presence of the surface film, where the amount of attachment, extracellular polymeric substance production, and cell proliferation on the coated surface was found to be greatly reduced compared to that obtained on the unmodified surface. This work suggests that the antimicrobial and antifouling coating used in this study could be effectively integrated into medical and other clinically relevant devices to prevent bacterial growth and to minimize bacteria-associated adverse host responses.
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THE LOSER LEAVES (Rome'S LOSS)
(2015) Geue, Tom
Juvenal's third satire is a privileged piece of verbal diarrhoea. As the longest satire in Juvenal's well-attended Book 1, as the centre of this book, and as the one Juvenalian jewel that sparkles 'non-rhetorically', it has always been the critics' darling. Its protagonist, on the other hand, has not always been so popular. Recently, reader sympathy for old Umbricius (the poem's main speaker) has shifted to laughter in his face; the old sense of 'pathetic' has ceded to the new. One of the central strategies of the 'Umbricius-as-caricature' camp has been to point to the overtime worked by 'mock-epic' in this poem: Umbricius self-inflates to become another Aeneas, fleeing a crumbling Troy (Rome). But an oppositio is wedged in imitando. Umbricius makes his lengthy verbal preparations to depart from Rome for Cumae; Aeneas had come to Rome through Cumae. Umbricius withdraws to set up shop in the meagre countryside; Aeneas had escaped to cap his exile teleologically with the (pre-foundation of the) Greatest City That Will Ever Be. Still, Virgil's paradigm tale of displacement, drift and re-establishment underlies Umbricius' self-definition as an exile. Indeed exile, with a large and ever-increasing stock of mythical and historical examples, was a situation ripe for self-mythologizing. Umbricius stands in Aeneas' shadow then, standing it on its head. His recession also makes him into a Iustitia/Dikē figure, the final trace of the golden age, off to alloy himself elsewhere. In his mind, exile is rationalized by distinguished past examples; in ours, we laugh at how disparate example and man really are. That side of Umbricius has been done to death; or at least, for present purposes, to exile.
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Explore space using swarms of tiny satellites
(2018-10-11) Levchenko, Igor; Keidar, Michael; Cantrell, Jim; Wu, Yue Liang; Kuninaka, Hitoshi; Bazaka, Kateryna; Xu, Shuyan
Sand-grain-sized computers, self-healing materials and constellations of craft would reboot our reach. [Figure not available: see fulltext.].
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Bandwagon, Underdog, or Projection? Opinion Polls and Electoral Choice in Britain, 1979–1987
(1991) McAllister, Ian
Since the widespread use of opinion polls in British general elections began in the 1950s, there has been continuing controversy concerning their impact on the vote. The bandwagon effect sees voters favoring a party that is doing well in the polls, while the underdog effect predicts that support will go to a party trailing in the polls. There is also the possibility of a projection effect, with voters expectations conforming to their partisanship. The results presented here, applying logistic regression to “exit poll survey data collected during the 1979, 1983, and 1987 British general election campaigns, find some evidence of a bandwagon effect in all three elections, but no evidence of an underdog effect and only minor evidence of a projection effect. However, there is a consistent interaction between poll influence and those who decided which way to vote during the election campaign, suggesting that opinion polls can facilitate tactical voting, especially in three-party competition.
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A Mononuclear, Low-Valent, Electron-Rich Osmium Methylene Complex
(1983) Hill, Anthony F.; Roper, Warren R.; Waters, Joyce M.; Wright, Anthony H.
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Technological advances have enhanced and expanded conservation genomics research but are yet to be integrated fully into biodiversity management
(2024) Neaves, Linda E.; Brockett, Brittany M.; Evans, Maldwyn J.; Pierson, Jennifer C.; Sarre, Stephen D.
Conservation genetics and genomics examines the role of evolutionary and genetic processes in the persistence of organisms, and its research is intended to inform biodiversity management. To characterize the fields within the discipline and map their trends over time and across the globe, we used text analysis to synthesize the peer-reviewed literature (n = 36,159). We then searched for reference to this literature in government documents to determine the frequency with which research was referenced. We found dramatic shifts in research topics associated with the advent of next generation sequencing, including the emergence of environmental DNA analyses. However, we also found a lag in the uptake of these methods, leaving markers such as microsatellites still widely used. Most research was undertaken in higher-income countries, while research involving lower-income countries was typically conducted though collaboration with higher-income countries. Although the number of peer-reviewed publications in the field has increased rapidly, the number referenced in biodiversity management documents has not, instead plateauing at ~10 % of publications since 2010. This suggests a growing disconnect between genomic research and its application. Similar topics attracted both academic citations and mentions in “on-the-ground” documentation, although some of the topics with increasing prevalence in research, such as genomic technologies, appeared less frequently in practice. Promoting co-design and long-term collaboration, rather than post hoc translation of research to application, could provide a more direct pathway for integration between research and governments by ensuring that the research is embraced by, and relevant to, stakeholders and on the ground conservation actions.
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An explanation of the stagnant under-5 mortality rate in Bangladesh using multilevel, multivariable analysis of three Demographic and Health Surveys
(2024-08-27) Mazumder, Tapas; Mohanty, Itismita; Ahmad, Danish; Niyonsenga, Theo
espite remarkable success in the Millennium Development Goal era, Bangladesh experienced a sluggish reduction in the under-5 mortality rate (U5MR) between 2014 and 2017–18. Our study aimed to explain this stagnancy by examining the variation in the key predictor-specific mortality risks over time, using the Bangladesh Demographic and Health Survey 2011, 2014 and 2017–18 data. We applied multilevel mixed effects logistic regression to examine the extent to which the under-5 mortality (U5M) risks were associated with the key sociodemographic and health service-specific predictors. We found that the rise in mortality risks attributable to maternal age 18 years or below, low maternal education, mother’s overweight or obesity and the absence of a handwashing station within the household were the key contributors to the stagnant U5MR between 2014 and 2017–18. Poverty and low education aggravated the mortality risks. Besides, antenatal care (ANC) and postnatal care (PNC) did not impact U5M risks as significantly as expected. Compulsory use of ANC and PNC cards and strict monitoring of their use may improve the quality of these health services. Leveraging committees like the Upazila Hospital Management Committee can bring harmony to implementing policies and programmes in the sectors related to U5M.
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Prediction of Global Functional Outcome and Post-Concussive Symptoms after Mild Traumatic Brain Injury
(2020) Mikolic, Ana; Polinder, Suzanne; Steyerberg, Ewout W.; Retel Helmrich, Isabel R. A.; Giacino, Joseph T.; Maas, Andrew I. R.; van der Naalt, Joukje; Voormolen, Daphne C.; von Steinbuechel, Nicole; Wilson, Lindsay; Lingsma, Hester F.; van Klaveren, David; Gruen, Russell
The majority of traumatic brain injuries (TBIs) are categorized as mild, according to a baseline Glasgow Coma Scale (GCS) score of 13-15. Prognostic models that were developed to predict functional outcome and persistent post-concussive symptoms (PPCS) after mild TBI have rarely been externally validated. We aimed to externally validate models predicting 3-12-month Glasgow Outcome Scale Extended (GOSE) or PPCS in adults with mild TBI. We analyzed data from the Collaborative European NeuroTrauma Effectiveness Research in Traumatic Brain Injury (CENTER-TBI) project, which included 2862 adults with mild TBI, with 6-month GOSE available for 2374 and Rivermead Post-Concussion Symptoms Questionnaire (RPQ) results available for 1605 participants. Model performance was evaluated based on calibration (graphically and characterized by slope and intercept) and discrimination (C-index). We validated five published models for 6-month GOSE and three for 6-month PPCS scores. The models used different cutoffs for outcome and some included symptoms measured 2 weeks post-injury. Discriminative ability varied substantially (C-index between 0.58 and 0.79). The models developed in the Corticosteroid Randomisation After Significant Head Injury (CRASH) trial for prediction of GOSE <5 discriminated best (C-index 0.78 and 0.79), but were poorly calibrated. The best performing models for PPCS included 2-week symptoms (C-index 0.75 and 0.76). In conclusion, none of the prognostic models for early prediction of GOSE and PPCS has both good calibration and discrimination in persons with mild TBI. In future studies, prognostic models should be tailored to the population with mild TBI, predicting relevant end-points based on readily available predictors.
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Data Protection Law and Emotion
(Oxford University Press, 2024-04-25) Clifford, Damian
Data protection law is often positioned as a regulatory solution to the risks posed by computational systems. This is logical given the pervasive data processing that underpins much of the technology we rely on daily. Despite the widespread adoption of data protection laws, however, there are those who remain very sceptical about their capacity to regulate these risks. Much of this criticism focuses on the role of us, the ‘data subjects’. For instance, it has been demonstrated repeatedly that we lack the capacity to act in our own best interests and, what is more, that our decisions have negative impacts on others. It is hard to dispute these points. Our decision-making limitations seem to be the inevitable by-product of the technological, social, and economic reality. The problems with data protection law also seem baked in through notions such as consent and the subjective control rights provided for in these frameworks and also the reliance on those processing our data to do so fairly. Despite these valid concerns, this book argues that the critiques of the instrumental role of control fail to recognize that its effectiveness is often more difficult to discern than the more critical literature would suggest, but it also emphasizes the importance of the conceptual value of subjective control. These points are analysed (and, indeed, exposed) by exploring data protection law through the lens of the insights provided by law and emotion scholarship.
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Local earthquake monitoring with a low-cost seismic network
(2024) Subedi, Shiba; Hetényi, György; Frédérick, Massin; Adhikari, Lok Bijaya; Michailos, Konstantinos
Seismic monitoring matters both for research and for populations living in areas of seismic hazard; however, it comes with a cost that is not fully affordable for developing countries. Compared to classical approaches with very quiet sites and high-quality instrumentation, it is therefore worth investigating low-cost seismic networks and how well they perform at detecting and characterizing seismicity. We analyze 1 year of seismic data from an educational seismology network in Nepal, create our own earthquake catalog, and compare it to the publicly available national observatory catalog. We find that despite the noisier seismic station sites, the overall results are comparable and all the main features relevant for seismicity are found. We present quantitative analyses of locations, magnitudes and their frequency distribution in our catalog, as well as differences with the observatory catalog. Differences between the two catalogs primarily stem from the respective network geometries and their coverage, as well as daytime noise level differences. We conclude that if properly planned and installed, low-cost seismic networks are a viable, feasible and significant complement to monitor seismic activity. Graphical Abstract: (Figure presented.)
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Should prioritising health interventions be informed by modelling studies? The case of cancer control in Aotearoa New Zealand
(2021-03-12) Wilson, Nick; Grout, Leah; Summers, Jennifer; Jones, Amanda C.; Mizdrak, Anja; Nghiem, Nhung; Cleghorn, Cristina; Blakely, Tony
In this viewpoint, we suggest that policymakers should prioritise health interventions by using evidence around health gain, impact on equity, health-system costs and cost-effectiveness. We take the example of the new cancer control agency in New Zealand, Te Aho o Te Kahu, and argue that its decision-making can now be informed by many methodologically compatible epidemiological and health economic analyses. These analyses span primary prevention of cancer (eg, tobacco control, dietary and physical activity interventions and HPV vaccination), cancer screening, cancer treatment and palliative care. The largest health gain and cost-savings from the available modelling work for New Zealand are seen in nutrition and tobacco control interventions in particular. Many of these interventions have potentially greater per capita health gain for Māori than non-Māori and are also found to be cost saving for the health sector. In summary, appropriate prioritisation of interventions can potentially both maximise health benefits as well as making best use of government funding of the health system.
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Potential impact of COVID-19 related unemployment on increased cardiovascular disease in a high-income country
(2021-05-27) Nghiem, Nhung; Wilson, Nick
Background: Cardiovascular disease (CVD) is a leading cause of health loss and health sector economic burdens in high-income countries. Unemployment is associated with increased risk of CVD, and so there is concern that the economic downturn associated with the COVID-19 pandemic will increase the CVD burden. Aims: This modeling study aimed to quantify potential health loss, health cost burden and health inequities among people with CVD due to additional unemployment caused by COVID-19 pandemic-related economic disruption in one high-income country: New Zealand (NZ). Methods: We adapted an established and validated multi-state life-table model for CVD in the national NZ population. We modeled indirect effects (ie, higher CVD incidence due to high unemployment rates) for various scenarios of pandemic-related unemployment projections from the NZ Treasury. Results: We estimated the potential CVD-related heath loss in NZ to range from 23,300 to 36,900 health-adjusted life years (HALYs) for the different unemployment scenarios. Health inequities would be increased with the per capita health loss for Māori (Indigenous population) estimated to be 3.7 times greater than for non-Māori (49.9 vs 13.5 HALYs lost per 1000 people). The estimated additional health system costs ranged between (NZ$303 million [m] to 503m in 2019 values; or US$209m to 346m). Conclusions and policy implications: Unemployment due to the COVID-19 pandemic could cause significant health loss, increase health inequities from CVD, and impose additional health system costs in this high-income country. Prevention measures should be considered by governments to reduce this risk, including additional job creation programs and measures directed towards the primary prevention of CVD.

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