Showing papers by "University of Wollongong published in 2003"

When Does Gender Trump Money? Bargaining and Time in Household Work

Abstract: Using data from Australia and the United States, the authors explore the effect of spouses’ contribution to family income on how housework is divided. Consistent with exchange‐bargaining theory, women decrease their housework as their earnings increase, up to the point where both spouses contribute equally to income. In other respects, gender trumps money. The base level of housework for women is much higher. Among the small percentage of couples who are in the range where women provide 51%–100% of household income, the change in housework is opposite what exchange theory predicts: couples that deviate from the normative income standard (men make more money than women) seem to compensate with a more traditional division of household work.

The experience of recovery from schizophrenia: towards an empirically validated stage model

Abstract: Objective: The consumer movement is advocating that rehabilitation services become recovery-orientated. The objectives of this study are to gain a better understanding of the concept of recovery by: (i) identifying a definition of recovery that reflects consumer accounts; and (ii) developing a conceptual model of recovery to guide research, training and inform clinical practice. Method: A review was conducted of published experiential accounts of recovery by people with schizophrenia or other serious mental illness, consumer articles on the concept of recovery, and qualitative research and theoretical literature on recovery. Meanings of recovery used by consumers were sought to identify a definition of recovery. Common themes identified in this literature were used to construct a conceptual model reflecting the personal experiences of consumers. Results: The definition of recovery used by consumers was identified as psychological recovery from the consequences of the illness. Four key processes of recovery were identified: (i) finding hope; (ii) re-establishment of identity; (iii) finding meaning in life; and (iv) taking responsibility for recovery. Five stages were identified: (i) moratorium; (ii) awareness; (iii) preparation; (iv) rebuilding; and (v) growth. Conclusion: A five-stage model compatible with psychological recovery is proposed, which offers a way forward for attaining recovery-orientated outcomes. After further empirical investigation, a version of this model could be utilized in quantitative research, clinical training and consumer education.

New ages for human occupation and climatic change at Lake Mungo, Australia

Abstract: Australia's oldest human remains, found at Lake Mungo, include the world's oldest ritual ochre burial (Mungo III) and the first recorded cremation (Mungo I). Until now, the importance of these finds has been constrained by limited chronologies and palaeoenvironmental information. Mungo III, the source of the world's oldest human mitochondrial DNA, has been variously estimated at 30 thousand years (kyr) old, 42-45 kyr old and 62 +/- 6 kyr old, while radiocarbon estimates placed the Mungo I cremation near 20-26 kyr ago. Here we report a new series of 25 optical ages showing that both burials occurred at 40 +/- 2 kyr ago and that humans were present at Lake Mungo by 50-46 kyr ago, synchronously with, or soon after, initial occupation of northern and western Australia. Stratigraphic evidence indicates fluctuations between lake-full and drier conditions from 50 to 40 kyr ago, simultaneously with increased dust deposition, human arrival and continent-wide extinction of the megafauna. This was followed by sustained aridity between 40 and 30 kyr ago. This new chronology corrects previous estimates for human burials at this important site and provides a new picture of Homo sapiens adapting to deteriorating climate in the world's driest inhabited continent.

Dangerous targets? Unresolved issues and ideological clashes around marine protected areas

Abstract: While conservationists, resource managers, scientists and coastal planners have recognized the broad applicability of marine protected areas (MPAs), they are often implemented without a firm understanding of the conservation science } both ecological and socio-economic } underlying marine protection. The rush to implement MPAs has set the stage for paradoxical differences of opinions in the marine conservation community. 2. The enthusiastic prescription of simplistic solutions to marine conservation problems risks polarization of interests and ultimately threatens bona fide progress in marine conservation. The blanket assignment and advocacy of empirically unsubstantiated rules of thumb in marine protection creates potentially dangerous targets for conservation science. 3. Clarity of definition, systematic testing of assumptions, and adaptive application of diverse MPA management approaches are needed so that the appropriate mix of various management tools can be utilized, depending upon specific goals and conditions. Scientists have a professional and

Digital rights management for content distribution

Abstract: Transferring the traditional business model for selling digital goods linked to physical media to the online world leads to the need for a system to protect digital intellectual property. Digital Rights Management(DRM) is a system to protect high-value digital assets and control the distribution and usage of those digital assets. This paper presents a review of the current state of DRM, focusing on security technologies, underlying legal implications and main obstacles to DRM deployment with the aim of providing a better understanding of what is currently happening to content management on a legal and technological basis and well prepared for grasping future prospects.

Radiochromic film for medical radiation dosimetry

Abstract: Photon, electron and proton radiations are used extensively for medical purposes in diagnostic and therapeutic procedures. Dosimetry of these radiation sources can be performed with radiochromic films, devices that have the ability to produce a permanent visible colour change upon irradiation. Within the last 10 years, the use of radiochromic films has expanded rapidly in the medical world due to commercial products becoming more readily available, higher sensitivity films and technology advances in imaging which have allowed scientists to use two-dimensional (2D) dosimetry more accurately and inexpensively. Radiochromic film dosimeters are now available in formats, which have accurate dose measurement ranges from less than 1 Gy up to many kGy. A relatively energy independent dose response combined with automatic development of radiochromic film products has made these detectors most useful in medical radiation dosimetry.

Mathematics teachers’ beliefs and curriculum reform

Abstract: This paper discusses the role of mathematics teachers’ beliefs and their impact on curriculum reform. It is argued that teachers’ beliefs about the teaching and learning mathematics are critical in determining the pace of curriculum reform. Educational change is a complex process in which teachers hold strong beliefs about the quality and the process of innovation. Curriculum implementation may only occur through sufferance as many teachers are suspicious of reform in mathematics education given its equivocal success over the past decades. It is not surprising then that many teachers, when they come to enact the curriculum in their classes, rely more on their own beliefs than on current trends in pedagogy. These beliefs, conservative as they might be, have their own rationality in the practical and daily nature of the teaching profession, and in the compelling influence of educational systems from which these teachers are paradoxically the social product. The literature indicates that many of these teachers hold behaviourist beliefs, a fact that has strong implications for the success of constructivist-oriented curriculum reform. In general, studies of teachers’ pedagogical beliefs reveal the extreme complexity of bringing about educational change, and largely explains the failure of many past reform endeavours.

Fundamentals of Computer Security

Abstract: From the Publisher: The book studies modern concepts of Computer Security. It is selfcontained in the sense that it introduces the basic mathematical background necessary to follow computer security concepts. Next we examine modern developments in Cryptography starting from private-key and public-key encryption, going through hashing, digital signatures, authentication, secret sharing, group-oriented cryptography, pseudorandomness, key establishment protocols, zero-knowledge protocols, identification and finishing with an introduction to modern e-business systems based on digital cash. Intrusion detection and access control provide examples of security systems implemented as a part of operating system. Database and network security is also discussed.

Use of Ionic Liquids as Electrolytes in Electromechanical Actuator Systems Based on Inherently Conducting Polymers

Abstract: The use of ionic liquids (ILs) as electrolytes for electromechanical actuators based on polypyrroles (PPy's) is described. The composition of the electrolytes has a significant effect on the electrochemical properties of the PPy actuator and subsequently on actuator performance, improving cycle life and strain generated. The actuator performance in ionic liquid electrolytes is significantly better than that in traditional organic and aqueous electrolytes.

Learned Resourcefulness Moderates the Relationship Between Academic Stress and Academic Performance

Abstract: People high in learned resourcefulness are purported to be better than others at controlling their negative emotions and managing stressful tasks. We hypothesised that highly resourceful students would be more effective than others at protecting themselves from the adverse effects of academic stress, and not allowing that stress to impact their grades. A sample of 141 first-year undergraduate students completed measures of academic stress and learned resourcefulness. Their first-year grade point averages were obtained from university records. Analyses revealed that academic stress was negatively associated with academic performance. As expected, this negative association was moderated by learned resourcefulness. High academic stress adversely impacted the grades of low resourceful students but had no effect on high resourceful students. We discuss the implications of these findings for improving academic performance.

Biosensors Based on Aligned Carbon Nanotubes Coated with Inherently Conducting Polymers

Abstract: The use of multiwalled aligned carbon nanotubes provides a novel electrode platform for inherently conducting polymer based biosensors. The example used here to highlight the usefulness of such a platform is the polypyrrole based glucose oxidase system for detection of glucose. The use of these three dimensional electrodes offers advantages in that large accessible enzyme loadings can be obtained within an ultrathin layer. It has also been found that the detection of H2O2 at these new electrode structures containing iron loaded nanotube tips can be achieved at low anodic potentials. The result is a sensitive and selective glucose sensor.

From PET detectors to PET scanners

Abstract: This review describes the properties of available and emerging radiation detector and read-out technologies and discusses how they may affect PET scanner performance. After a general introduction, there is a section in which the physical properties of several different detector scintillators are compared. This is followed by a discussion of recent advances in read-out electronics. Finally, the physical performance of the several commercial PET scanners is summarized.

Living on the edge-plants and global change in continental and maritime Antarctica

Abstract: Antarctic terrestrial ecosystems experience some of the most extreme growth conditions on Earth and are characterized by extreme aridity and subzero temperatures. Antarctic vegetation is therefore at the physiological limits of survival and, as a consequence, even slight changes to growth conditions are likely to have a large impact, rendering Antarctic terrestrial communities sensitive to climate change. Climate change is predicted to affect the high-latitude regions first and most severely. In recent decades, the Antarctic has undergone significant environmental change, including the largest increases in ultraviolet-B (UV-B; 290–320 nm) radiation levels in the world and, in the maritime region at least, significant temperature increases. This review describes the current evidence for environmental change in Antarctica, and the impacts of this change on the terrestrial vegetation. This is largely restricted to cryptogams, such as bryophytes, lichens and algae; only two vascular plant species occur in the Antarctic, both restricted to the maritime region. We review the range of ecological and physiological consequences of increasing UV-B radiation levels, and of changes in temperature, water relations and nutrient availability. It is clear that climate change is already affecting the Antarctic terrestrial vegetation, and significant impacts are likely to continue in the future. We conclude that, in order to gain a better understanding of the complex dynamics of this important system, there is a need for more manipulative, longterm field experiments designed to address the impacts of changes in multiple abiotic factors on the Antarctic flora.

MPEG-21: goals and achievements

Abstract: MPEG-21 is an open standards-based framework for multimedia delivery and consumption. It aims to enable the use of multimedia resources across a wide range of networks and devices. We discuss MPEG-21's parts, achievements, ongoing activities, and opportunities for new technologies.

Poly(2-alkylacrylic acid) polymers deliver molecules to the cytosol by pH-sensitive disruption of endosomal vesicles.

Abstract: The permeability barrier posed by cell membranes represents a challenge for the delivery of hydrophilic molecules into cells. We previously proposed that poly(2-alkylacrylic acid)s are endocytosed by cells into acidified vesicles and are there triggered by low pH to disrupt membranes and release the contents of endosomes/lysosomes to the cytosol. If this hypothesis is correct, these polymers could be valuable in drug-delivery applications. The present paper reports functional comparisons of a family of three poly(2-alkylacrylic acid)s. Poly(2-propylacrylic acid) (PPAA), poly(2-ethylacrylic acid) (PEAA) and poly(2-methylacrylic acid) (PMAA) were compared in red-blood-cell haemolysis assays and in a lipoplex (liposome-DNA complex) assay. We also directly examined the ability of these polymers to disrupt endosomes and lysosomes in cultured human cells. Our results show that: (i) unlike membrane-disruptive peptides, the endosomal-disruptive ability of poly(2-alkylacrylic acid)s cannot necessarily be predicted from their haemolytic activity at low pH, (ii) PPAA (but not PEAA or PMAA) potently facilitates gene transfection by cationic lipoplexes and (iii) endocytosed poly(2-alkylacrylic acid)s are triggered by luminal acidification to selectively disrupt endosomes (not lysosomes) and release their contents to the cytosol. These results will facilitate the rational design of future endosomal-disrupting polymers for drug delivery.

Who's Driving the Asylum Debate? Newspaper and Government Representations of Asylum Seekers

Abstract: The welfare and future of asylum seekers in Australia have been very contentious contemporary issues. Findings based on content analysis of media releases in 2001 and 2002 reveal the unrelentingly negative way in which the federal government portrayed asylum seekers. While the government's negative tenor was constant during the study period, the specific terms of reference altered, from 'threat' through 'other', to 'illegality' and to 'burden'. The negative construction of asylum seekers was clearly mutable. Analysis of newspaper reporting during the same period indicates that the media largely adopted the negativity and specific references of the government. The media dependence upon government statements and spokespersons in part explains this relation. The findings generally support the 'propaganda model' that holds a pessimistic view of the news media's critical abilities. However, the media departed somewhat slightly from the government's unchanging stance following some key events and revelations. Clearly, there is scope for disrupting the flow of negative constructions from government to media, and ultimately to audiences.

A self-organizing map for adaptive processing of structured data

Abstract: Recent developments in the area of neural networks produced models capable of dealing with structured data. Here, we propose the first fully unsupervised model, namely an extension of traditional self-organizing maps (SOMs), for the processing of labeled directed acyclic graphs (DAGs). The extension is obtained by using the unfolding procedure adopted in recurrent and recursive neural networks, with the replicated neurons in the unfolded network comprising of a full SOM. This approach enables the discovery of similarities among objects including vectors consisting of numerical data. The capabilities of the model are analyzed in detail by utilizing a relatively large data set taken from an artificial benchmark problem involving visual patterns encoded as labeled DAGs. The experimental results demonstrate clearly that the proposed model is capable of exploiting both information conveyed in the labels attached to each node of the input DAGs and information encoded in the DAG topology.

Life, death and membrane bilayers.

Abstract: Membrane bilayers are essential elements of life, and the synthesis of the hydrocarbons that make up membrane bilayers may have preceded the appearance of life on Earth. Membrane-associated processes are significant components of metabolism, and the acyl composition of membrane bilayers is associated with metabolic activity in a predictable manner. This has resulted in the "membrane pacemaker" theory of metabolism, which proposes that the relative balance between monounsaturated and long-chain polyunsaturated acyl chains in membrane bilayers is a fundamental determinant of metabolic rate of a species. The omega-3 polyunsaturated docosahexaenoate is an especially important component of membranes in this regard. Whilst it is suggested that the physical properties of membrane polyunsaturates are important with respect to their influence on metabolic rate, it is their chemistry that is important in aging. Membrane acyl composition is related to maximum lifespan in mammals and birds, probably via their role in lipid peroxidation. Calorie restriction modifies acyl composition of membrane bilayers and is associated with decreased membrane lipid peroxidation and lifespan extension. The membrane pacemaker theory of metabolism has given birth to the membrane pacemaker hypothesis of aging, which will require further investigation.

Spatial and temporal variation in spectral reflectance: Are seagrass species spectrally distinct?

Abstract: The spectral signatures of the seagrasses Zostera capricorni, Posidonia australis, and Halophila ovalis were investigated to determine whether species could be discriminated by remote sensing. The spectral reflectance of fouled and unfouled leaf samples collected from marine and brackish habitats at three estuaries in southeastern Australia were measured in the field with a spectroradiometer during each season in 1999 and 2000. Seagrass species were spectrally distinct regardless of whether the leaves were fouled by epibionts and despite spatial and temporal variability in the reflectance of each species. The visible wavelengths that penetrate water coincide with the regions of maximum absorption and characteristic reflectance by plant photosynthetic and accessory pigments. Strong and consistent differences in reflectance between species were recorded in the green wavelengths at 530‐ 580 nm with additional discrimination in the regions 520‐530 nm and 580‐600 nm and at the red chlorophyll absorption trough at 686‐700 nm. Species discrimination should be possible in the remote sensing of benthic aquatic vegetation using a hyperspectral sensor that has narrow bands centered on pigment-related spectral features in the visible wavelengths. The detection of statistically significant differences in intraspecific reflectance associated with the year, season, estuary, and habitat of sample collection suggests a potential for monitoring seagrass health and estuarine water quality. This study has produced the first spectral library of aquatic plant species to take into account the range of spectral variability expected for the species under natural conditions. The results provide a sound basis for future mapping of seagrass species in Australia.

Effect of carbon nanotube doping on critical current density of MgB2 superconductor

Abstract: The effect of doping MgB2 with carbon nanotubes on transition temperature, lattice parameters, critical current density and flux pinning was studied for MgB2−xCx with x=0, 0.05, 0.1, 0.2, and 0.3. The carbon substitution for B was found to enhance Jc in magnetic fields but depress Tc. The depression of Tc, which is caused by the carbon substitution for B, increases with an increasing doping level, sintering temperature, and duration. By controlling the extent of the substitution and addition of carbon nanotubes we can achieve the optimal improvement on critical current density and flux pinning in magnetic fields while maintaining the minimum reduction in Tc. Under these conditions, Jc was enhanced by two orders of magnitude at 8 T and 5 K and 7 T and 10 K. Jc was more than 10 000 A/cm2 at 20 K and 4 T and 5 K and 8.5 T, respectively.

Small heat-shock proteins and clusterin: intra- and extracellular molecular chaperones with a common mechanism of action and function?

Abstract: Small heat-shock proteins (sHsps) and clusterin are molecular chaperones that share many functional similarities despite their lack of significant sequence similarity. These functional similarities, and some differences, are discussed. sHsps are ubiquitous intracellular proteins whereas clusterin is generally found extracellularly. Both chaperones potently prevent the amorphous aggregation and precipitation of target proteins under stress conditions such as elevated temperature, reduction and oxidation. In doing so, they act on the slow, off-folding protein pathway. The conformational dynamism and aggregated state of both proteins may be crucial for their chaperone function. Subunit exchange is likely to be important in regulating chaperone action; the dissociated form of the protein is probably the chaperone-active species rather than the aggregated state. They both exert their chaperone action without the need for hydrolysis of ATP and have little ability to refold target proteins. Increased expression of sHsps and clusterin accompanies a range of diseases that arise from protein misfolding and deposition of highly structured protein aggregates known as amyloid fibrils, e.g., Alzheimer's, Creutzfeldt-Jakob and Parkinson's diseases. The interaction of sHsps and clusterin with fibril-forming species is discussed along with their ability to prevent fibril formation.