Showing papers by "University of New South Wales published in 2007"

Clinical diagnostic criteria for dementia associated with Parkinson's disease.

Abstract: Dementia has been increasingly more recognized to be a common feature in patients with Parkinson's disease (PD), especially in old age. Specific criteria for the clinical diagnosis of dementia associated with PD (PD-D), however, have been lacking. A Task Force, organized by the Movement Disorder Study, was charged with the development of clinical diagnostic criteria for PD-D. The Task Force members were assigned to sub-committees and performed a systematic review of the literature, based on pre-defined selection criteria, in order to identify the epidemiological, clinical, auxillary, and pathological features of PD-D. Clinical diagnostic criteria were then developed based on these findings and group consensus. The incidence of dementia in PD is increased up to six times, point-prevelance is close to 30%, older age and akinetic-rigid form are associated with higher risk. PD-D is characterized by impairment in attention, memory, executive and visuo-spatial functions, behavioral symptoms such as affective changes, hallucinations, and apathy are frequent. There are no specific ancillary investigations for the diagnosis; the main pathological correlate is Lewy body-type degeneration in cerebral cortex and limbic structures. Based on the characteristic features associated with this condition, clinical diagnostic criteria for probable and possible PD-D are proposed.

Updated research nosology for HIV-associated neurocognitive disorders

Abstract: In 1991, the AIDS Task Force of the American Academy of Neurology published nomenclature and research case definitions to guide the diagnosis of neurologic manifestations of HIV-1 infection. Now, 16 years later, the National Institute of Mental Health and the National Institute of Neurological Diseases and Stroke have charged a working group to critically review the adequacy and utility of these definitional criteria and to identify aspects that require updating. This report represents a majority view, and unanimity was not reached on all points. It reviews our collective experience with HIV-associated neurocognitive disorders (HAND), particularly since the advent of highly active antiretroviral treatment, and their definitional criteria; discusses the impact of comorbidities; and suggests inclusion of the term asymptomatic neurocognitive impairment to categorize individuals with subclinical impairment. An algorithm is proposed to assist in standardized diagnostic classification of HAND.

The predictive validity of multiple-item versus single-item measures of the same constructs

Abstract: This study compares the predictive validity of single-item and multiple-item measures of attitude toward the ad (AAd) and attitude toward the brand (ABrand), which are two of the most widely measured constructs in marketing. The authors assess the ability of AAd to predict ABrand in copy tests of four print advertisements for diverse new products. There is no difference in the predictive validity of the multiple-item and single-item measures. The authors conclude that for the many constructs in marketing that consist of a concrete singular object and a concrete attribute, such as AAd or ABrand, single-item measures should be used.

The delayed rise of present-day mammals

Abstract: Did the end-Cretaceous mass extinction event, by eliminating non-avian dinosaurs and most of the existing fauna, trigger the evolutionary radiation of present-day mammals? Here we construct, date and analyse a species-level phylogeny of nearly all extant Mammalia to bring a new perspective to this question. Our analyses of how extant lineages accumulated through time show that net per-lineage diversification rates barely changed across the Cretaceous/Tertiary boundary. Instead, these rates spiked significantly with the origins of the currently recognized placental superorders and orders approximately 93 million years ago, before falling and remaining low until accelerating again throughout the Eocene and Oligocene epochs. Our results show that the phylogenetic 'fuses' leading to the explosion of extant placental orders are not only very much longer than suspected previously, but also challenge the hypothesis that the end-Cretaceous mass extinction event had a major, direct influence on the diversification of today's mammals.

Agronomic values of greenwaste biochar as a soil amendment

Abstract: A pot trial was carried out to investigate the effect of biochar produced from greenwaste by pyrolysis on the yield of radish (Raphanus sativus var. Long Scarlet) and the soil quality of an Alfisol. Three rates of biochar (10, 50 and 100 t/ha) with and without additional nitrogen application (100 kg N/ha) were investigated. The soil used in the pot trial was a hardsetting Alfisol (Chromosol) (0–0.1 m) with a long history of cropping. In the absence of N fertiliser, application of biochar to the soil did not increase radish yield even at the highest rate of 100 t/ha. However, a significant biochar × nitrogen fertiliser interaction was observed, in that higher yield increases were observed with increasing rates of biochar application in the presence of N fertiliser, highlighting the role of biochar in improving N fertiliser use efficiency of the plant. For example, additional increase in DM of radish in the presence of N fertiliser varied from 95% in the nil biochar control to 266% in the 100 t/ha biochar-amended soils. A slight but significant reduction in dry matter production of radish was observed when biochar was applied at 10 t/ha but the cause is unclear and requires further investigation. Significant changes in soil quality including increases in pH, organic carbon, and exchangeable cations as well as reduction in tensile strength were observed at higher rates of biochar application (>50 t/ha). Particularly interesting are the improvements in soil physical properties of this hardsetting soil in terms of reduction in tensile strength and increases in field capacity.

Statistical Mechanics of Nonequilibrium Liquids

Abstract: 1. Introduction 2. Linear irreversible thermodynamics 3. The microscopic connection 4. The Green-Kubo relations 5. Linear response theory 6. Computer simulation algorithms 7. Nonlinear response theory 8. Dynamical stability 9. Nonequilibrium fluctuations 10. Thermodynamics of steady states References Index.

Sequential Monte Carlo without likelihoods

Abstract: Recent new methods in Bayesian simulation have provided ways of evaluating posterior distributions in the presence of analytically or computationally intractable likelihood functions. Despite representing a substantial methodological advance, existing methods based on rejection sampling or Markov chain Monte Carlo can be highly inefficient and accordingly require far more iterations than may be practical to implement. Here we propose a sequential Monte Carlo sampler that convincingly overcomes these inefficiencies. We demonstrate its implementation through an epidemiological study of the transmission rate of tuberculosis.

Five Essential Elements of Immediate and Mid–Term Mass Trauma Intervention: Empirical Evidence

Abstract: Given the devastation caused by disasters and mass violence, it is critical that intervention policy be based on the most updated research findings. However, to date, no evidence-based consensus has been reached supporting a clear set of recommendations for intervention during the immediate and the mid-term post mass trauma phases. Because it is unlikely that there will be evidence in the near or mid-term future from clinical trials that cover the diversity of disaster and mass violence circumstances, we assembled a worldwide panel of experts on the study and treatment of those exposed to disaster and mass violence to extrapolate from related fields of research, and to gain consensus on intervention principles. We identified five empirically supported intervention principles that should be used to guide and inform intervention and prevention efforts at the early to mid-term stages. These are promoting: 1) a sense of safety, 2) calming, 3) a sense of self- and community efficacy, 4) connectedness, and 5) hope.

Assurance on Sustainability Reports: An International Comparison

Abstract: Globally, companies increasingly publish separate general purpose, non-financial (sustainability) reports. Some of these are independently assured and assurers may or may not be from the auditing profession. We seek to understand this emerging voluntary assurance market. Using a sample of 2,113 companies (from 31 countries) that produced sustainability reports between 2002-2004, we use sequential logit analysis to identify the factors associated with the decision to voluntarily purchase assurance and the choice of assurance provider. We hypothesize that a company's need to enhance credibility through assurance and choice of assurance provider will be a function of company, industry and country-related factors. Our results support the argument that companies seeking to enhance the credibility of their reports and build their corporate reputation are more likely to have their sustainability reports assured, although it does not matter whether the assurance provider comes from the auditing profession. We also find that companies operating in stakeholder orientated countries are more likely to choose the auditing profession as an assurer.

Early human use of marine resources and pigment in South Africa during the Middle Pleistocene

Abstract: Genetic and anatomical evidence suggests that Homo sapiens arose in Africa between 200 and 100 thousand years (kyr) ago, and recent evidence indicates symbolic behaviour may have appeared approximately 135-75 kyr ago. From 195-130 kyr ago, the world was in a fluctuating but predominantly glacial stage (marine isotope stage MIS6); much of Africa was cooler and drier, and dated archaeological sites are rare. Here we show that by approximately 164 kyr ago (+/-12 kyr) at Pinnacle Point (on the south coast of South Africa) humans expanded their diet to include marine resources, perhaps as a response to these harsh environmental conditions. The earliest previous evidence for human use of marine resources and coastal habitats was dated to approximately 125 kyr ago. Coincident with this diet and habitat expansion is an early use and modification of pigment, probably for symbolic behaviour, as well as the production of bladelet stone tool technology, previously dated to post-70 kyr ago. Shellfish may have been crucial to the survival of these early humans as they expanded their home ranges to include coastlines and followed the shifting position of the coast when sea level fluctuated over the length of MIS6.

Liquidity and Market Efficiency

Abstract: Market efficiency, the timely incorporation of information into prices, remains a central and controversial issue in finance. The short-horizon predictability of returns from past order flows is an inverse indicator of efficiency. We analyze this predictability for NYSE stocks that traded every day from 1993 through 2002. Mid-quote return predictability is diminished when bid-ask spreads are narrower. Such predictability has declined over time with the minimum tick size. Variance ratios of five-minute and daily returns suggest that prices were closer to random walk benchmarks during decimal regimes than during regimes with higher tick sizes (and wider spreads). These findings support the notion that liquidity stimulates arbitrage activity, which, in turn, enhances market efficiency. Further, as the tick size decreased, open-close/close-open return variance ratios increased, while return autocorrelations decreased. This suggests an increased incorporation of private information into prices during more liquid regimes.

The concept of hydrological connectivity and its contribution to understanding runoff‐dominated geomorphic systems

Abstract: The term 'connectivity' is increasingly being applied in hydrological and geomorphological studies. Relevant research encompasses aspects of landscape connectivity, hydrological connectivity and sedimentological connectivity. Unlike other disciplines, notably ecology, published studies show no consensus on a standard definition. This paper provides an overview of how existing research relates to the concept of connectivity in both ecology and hydrology by proposing and evaluating a conceptual model of hydrological connectivity that includes five major components: climate; hillslope runoff potential; landscape position; delivery pathway and lateral connectivity. We also evaluate a proposed measure of connectivity called the volume to breakthrough to quantify changing connectivity between different environments and catchments.

Expertise Reversal Effect and Its Implications for Learner-Tailored Instruction

Abstract: The interactions between levels of learner prior knowledge and effectiveness of different instructional techniques and procedures have been intensively investigated within a cognitive load framework since mid-90s. This line of research has become known as the expertise reversal effect. Apart from their cognitive load theory-based prediction and explanation, patterns of empirical findings on the effect fit well those in studies of Aptitude Treatment Interactions (ATI) that were originally initiated in mid-60s. This paper reviews recent empirical findings associated with the expertise reversal effect, their interpretation within cognitive load theory, relations to ATI studies, implications for the design of learner-tailored instructional systems, and some recent experimental attempts of implementing these findings into realistic adaptive learning environments.

The minimum information about a proteomics experiment (MIAPE)

Abstract: Both the generation and the analysis of proteomics data are now widespread, and high-throughput approaches are commonplace. Protocols continue to increase in complexity as methods and technologies evolve and diversify. To encourage the standardized collection, integration, storage and dissemination of proteomics data, the Human Proteome Organization's Proteomics Standards Initiative develops guidance modules for reporting the use of techniques such as gel electrophoresis and mass spectrometry. This paper describes the processes and principles underpinning the development of these modules; discusses the ramifications for various interest groups such as experimentalists, funders, publishers and the private sector; addresses the issue of overlap with other reporting guidelines; and highlights the criticality of appropriate tools and resources in enabling 'MIAPE-compliant' reporting.

Analysis of minimal residual disease by Ig/TCR gene rearrangements: guidelines for interpretation of real-time quantitative PCR data.

Abstract: Most modern treatment protocols for acute lymphoblastic leukaemia (ALL) include the analysis of minimal residual disease (MRD). To ensure comparable MRD results between different MRD-polymerase chain reaction (PCR) laboratories, standardization and quality control are essential. The European Study Group on MRD detection in ALL (ESG-MRD-ALL), consisting of 30 MRD-PCR laboratories worldwide, has developed guidelines for the interpretation of real-time quantitative PCR-based MRD data. The application of these guidelines ensures identical interpretation of MRD data between different laboratories of the same MRD-based clinical protocol. Furthermore, the ESG-MRD-ALL guidelines will facilitate the comparison of MRD data obtained in different treatment protocols, including those with new drugs.

Carbon nanotubes for biological and biomedical applications

Abstract: Ever since the discovery of carbon nanotubes, researchers have been exploring their potential in biological and biomedical applications. The recent expansion and availability of chemical modification and bio-functionalization methods have made it possible to generate a new class of bioactive carbon nanotubes which are conjugated with proteins, carbohydrates, or nucleic acids. The modification of a carbon nanotube on a molecular level using biological molecules is essentially an example of the 'bottom-up' fabrication principle of bionanotechnology. The availability of these biomodified carbon nanotube constructs opens up an entire new and exciting research direction in the field of chemical biology, finally aiming to target and to alter the cell's behaviour at the subcellular or molecular level. This review covers the latest advances of bio-functionalized carbon nanotubes with an emphasis on the development of functional biological nano-interfaces. Topics that are discussed herewith include methods for biomodification of carbon nanotubes, the development of hybrid systems of carbon nanotubes and biomolecules for bioelectronics, and carbon nanotubes as transporters for a specific delivery of peptides and/or genetic material to cells. All of these current research topics aim at translating these biotechnology modified nanotubes into potential novel therapeutic approaches.

Evaluation of the AR4 Climate Models’ Simulated Daily Maximum Temperature, Minimum Temperature, and Precipitation over Australia Using Probability Density Functions

Abstract: The coupled climate models used in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change are evaluated The evaluation is focused on 12 regions of Australia for the daily simulation of precipitation, minimum temperature, and maximum temperature The evaluation is based on probability density functions and a simple quantitative measure of how well each climate model can capture the observed probability density functions for each variable and each region is introduced Across all three variables, the coupled climate models perform better than expected Precipitation is simulated reasonably by most and very well by a small number of models, although the problem with excessive drizzle is apparent in most models Averaged over Australia, 3 of the 14 climate models capture more than 80% of the observed probability density functions for precipitation Minimum temperature is simulated well, with 10 of the 13 climate models capturing more than 80% of the observed probability densit

Use of 16S rRNA and rpoB genes as molecular markers for microbial ecology studies.

Abstract: Several characteristics of the 16S rRNA gene, such as its essential function, ubiquity, and evolutionary properties, have allowed it to become the most commonly used molecular marker in microbial ecology However, one fact that has been overlooked is that multiple copies of this gene are often present in a given bacterium These intragenomic copies can differ in sequence, leading to identification of multiple ribotypes for a single organism To evaluate the impact of such intragenomic heterogeneity on the performance of the 16S rRNA gene as a molecular marker, we compared its phylogenetic and evolutionary characteristics to those of the single-copy gene rpoB Full-length gene sequences and gene fragments commonly used for denaturing gradient gel electrophoresis were compared at various taxonomic levels Heterogeneity found between intragenomic 16S rRNA gene copies was concentrated in specific regions of rRNA secondary structure Such “heterogeneity hot spots” occurred within all gene fragments commonly used in molecular microbial ecology This intragenomic heterogeneity influenced 16S rRNA gene tree topology, phylogenetic resolution, and operational taxonomic unit estimates at the species level or below rpoB provided comparable phylogenetic resolution to that of the 16S rRNA gene at all taxonomic levels, except between closely related organisms (species and subspecies levels), for which it provided better resolution This is particularly relevant in the context of a growing number of studies focusing on subspecies diversity, in which single-copy protein-encoding genes such as rpoB could complement the information provided by the 16S rRNA gene

Corporate Governance and Board Composition: diversity and independence of Australian boards

Abstract: The board of directors is one of a number of internal governance mechanisms that are intended to ensure that the interests of shareholders and managers are closely aligned, and to discipline or remove ineffective management teams. Among the most significant governance issues currently faced by the modern corporation are those relating to diversity, such as gender and age, and independence of directors. While board diversity and independence has been a growing area of research in recent years, most empirical research on this topic has been restricted to US data. The generalisability of such findings may not extend across national boundaries due to different regulatory and economic environments, cultural differences, the size of capital markets and the effectiveness of governance mechanisms. Consequently, the importance and value of various governance structures, including board diversity and independence, should be separately examined in each country, and the influential factors investigated. This study reports on the diversity and independence of the board membership of 100 top Australian companies in 2003. Australia has one of the most developed stock markets in the Asia-Pacific region. With the collapse of several well-known public companies such as Ansett, OneTel and HIH, there is an increasing demand to evaluate the corporate governance practices of Australian companies, including the composition of boards. Accordingly, this research provides a timely review of the state of corporate governance in Australia so far as board composition is concerned.

Central Blood Pressure Measurements and Antihypertensive Therapy: A Consensus Document

Abstract: The 2003 European Society of Hypertension/European Society of Cardiology guidelines for the management of arterial hypertension1 included 2 important novel recommendations: assessment of the total cardiovascular risk should be taken into account in the management of the hypertensive patient, and quantification of risk should include subclinical target organ damage. These guidelines acknowledged that central (aortic) blood pressure (BP), which is the pressure exerted on the heart and brain, may be different from the pressure that is measured at the arm. They also recognized that central pressure may be predictive of outcome in specific populations2 and differently affected by antihypertensive drugs. However, although these guidelines accepted that central augmentation index and pulse wave velocity may be important as measures of subclinical organ damage, they also stressed the need for prospective trials to establish their predictive values given that such studies were lacking at that time (2003). After publication of these guidelines, additional data have strengthened the pathophysiological importance of central BP. Clinical studies have indicated that central BP may have predictive value independent of the corresponding peripheral (brachial) BP. More importantly, recent large-scale trials have shown that central hemodynamics may provide a worthwhile treatment target. In addition, central hemodynamics can now be reliably assessed noninvasively with a number of devices. Accordingly, because arterial stiffening and central hemodynamics are markers and manifestations of organ damage, the pertinent key question is whether the balance of evidence on their importance and issues related to clinical practice allows for implementation in patient management. Central (aortic and carotid) pressures are pathophysiologically more relevant than peripheral pressures for the pathogenesis of cardiovascular disease.3,4 It is aortic systolic pressure that the left ventricle encounters during systole (afterload), and the aortic pressure during diastole is a determinant of coronary perfusion. Furthermore, the distending pressure in the …

Shiga toxin induces tubular membrane invaginations for its uptake into cells

Abstract: Clathrin seems to be dispensable for some endocytic processes and, in several instances, no cytosolic coat protein complexes could be detected at sites of membrane invagination. Hence, new principles must in these cases be invoked to account for the mechanical force driving membrane shape changes. Here we show that the Gb3 (glycolipid)-binding B-subunit of bacterial Shiga toxin induces narrow tubular membrane invaginations in human and mouse cells and model membranes. In cells, tubule occurrence increases on energy depletion and inhibition of dynamin or actin functions. Our data thus demonstrate that active cellular processes are needed for tubule scission rather than tubule formation. We conclude that the B-subunit induces lipid reorganization that favours negative membrane curvature, which drives the formation of inward membrane tubules. Our findings support a model in which the lateral growth of B-subunit–Gb3 microdomains is limited by the invagination process, which itself is regulated by membrane tension. The physical principles underlying this basic cargo-induced membrane uptake may also be relevant to other internalization processes, creating a rationale for conceptualizing the perplexing diversity of endocytic routes. An imaging study of an early step of bacterial toxin intake into cells — membrane invagination — reveals a cargo-induced mechanism that may also apply to other pathogens and more generally to other endocytosis events. The B subunit of Shiga toxin (from Shigella dysenteriae) is seen to enter cells via narrow tubular membrane invaginations. The toxin induces membrane reorganization prior to formation of tubular invaginations, which occurs independently of protein complexes (like clathrin) that have been ascribed membrane deforming capacities, and also when cellular energy is depleted. So membrane invagination relies on physical principles and can occur spontaneously, without the need for sophisticated cellular machinery. A study of endocytosis of Shigella toxin shows that it enters cells via narrow tubular membrane invaginations, with similar properties on cell and model membranes. The toxin induces membrane reorganisation before the formation of tubular invaginations.

DNA stable-isotope probing

Abstract: Stable-isotope probing is a method used in microbial ecology that provides a means by which specific functional groups of organisms that incorporate particular substrates are identified without the prerequisite of cultivation. Stable-isotope-labeled carbon (13C) or nitrogen (15N) sources are assimilated into microbial biomass of environmental samples. Separation and molecular analysis of labeled nucleic acids (DNA or RNA) reveals phylogenetic and functional information about the microorganisms responsible for the metabolism of a particular substrate. Here, we highlight general guidelines for incubating environmental samples with labeled substrate and provide a detailed protocol for separating labeled DNA from unlabeled community DNA. The protocol includes a modification of existing published methods, which maximizes the recovery of labeled DNA from CsCl gradients. The separation of DNA and retrieval of unlabeled and labeled fractions can be performed in 4-5 days, with much of the time being committed to the ultracentrifugation step.

Excess lipid availability increases mitochondrial fatty acid oxidative capacity in muscle: evidence against a role for reduced fatty acid oxidation in lipid-induced insulin resistance in rodents.

Abstract: A reduced capacity for mitochondrial fatty acid oxidation in skeletal muscle has been proposed as a major factor leading to the accumulation of intramuscular lipids and their subsequent deleterious effects on insulin action. Here, we examine markers of mitochondrial fatty acid oxidative capacity in rodent models of insulin resistance associated with an oversupply of lipids. C57BL/6J mice were fed a high-fat diet for either 5 or 20 weeks. Several markers of muscle mitochondrial fatty acid oxidative capacity were measured, including 14C-palmitate oxidation, palmitoyl-CoA oxidation in isolated mitochondria, oxidative enzyme activity (citrate synthase, β-hydroxyacyl CoA dehydrogenase, medium-chain acyl-CoA dehydrogenase, and carnitine palmitoyl-transferase 1), and expression of proteins involved in mitochondrial metabolism. Enzyme activity and mitochondrial protein expression were also examined in muscle from other rodent models of insulin resistance. Compared with standard diet–fed controls, muscle from fat-fed mice displayed elevated palmitate oxidation rate (5 weeks +23%, P < 0.05, and 20 weeks +29%, P < 0.05) and increased palmitoyl-CoA oxidation in isolated mitochondria (20 weeks +49%, P < 0.01). Furthermore, oxidative enzyme activity and protein expression of peroxisome proliferator–activated receptor γ coactivator (PGC)-1α, uncoupling protein (UCP) 3, and mitochondrial respiratory chain subunits were significantly elevated in fat-fed animals. A similar pattern was present in muscle of fat-fed rats, obese Zucker rats, and db/db mice, with increases observed for oxidative enzyme activity and expression of PGC-1α, UCP3, and subunits of the mitochondrial respiratory chain. These findings suggest that high lipid availability does not lead to intramuscular lipid accumulation and insulin resistance in rodents by decreasing muscle mitochondrial fatty acid oxidative capacity.

Probabilistic skylines on uncertain data

Abstract: Uncertain data are inherent in some important applications. Although a considerable amount of research has been dedicated to modeling uncertain data and answering some types of queries on uncertain data, how to conduct advanced analysis on uncertain data remains an open problem at large. In this paper, we tackle the problem of skyline analysis on uncertain data. We propose a novel probabilistic skyline model where an uncertain object may take a probability to be in the skyline, and a p-skyline contains all the objects whose skyline probabilities are at least p. Computing probabilistic skylines on large uncertain data sets is challenging. We develop two efficient algorithms. The bottom-up algorithm computes the skyline probabilities of some selected instances of uncertain objects, and uses those instances to prune other instances and uncertain objects effectively. The top-down algorithm recursively partitions the instances of uncertain objects into subsets, and prunes subsets and objects aggressively. Our experimental results on both the real NBA player data set and the benchmark synthetic data sets show that probabilistic skylines are interesting and useful, and our two algorithms are efficient on large data sets, and complementary to each other in performance.