Showing papers by "University of South Australia published in 1996"

Competitive Markov decision processes

Abstract: 1 Introduction.- 1.0 Background.- 1.1 Raison d'Etre and Limitations.- 1.2 A Menu of Courses and Prerequisites.- 1.3 For the Cognoscenti.- 1.4 Style and Nomenclature.- I Mathematical Programming Perspective.- 2 Markov Decision Processes: The Noncompetitive Case.- 2.0 Introduction.- 2.1 The Summable Markov Decision Processes.- 2.2 The Finite Horizon Markov Decision Process.- 2.3 Linear Programming and the Summable Markov Decision Models.- 2.4 The Irreducible Limiting Average Process.- 2.5 Application: The Hamiltonian Cycle Problem.- 2.6 Behavior and Markov Strategies.- 2.7 Policy Improvement and Newton's Method in Summable MDPs.- 2.8 Connection Between the Discounted and the Limiting Average Models.- 2.9 Linear Programming and the Multichain Limiting Average Process.- 2.10 Bibliographic Notes.- 2.11 Problems.- 3 Stochastic Games via Mathematical Programming.- 3.0 Introduction.- 3.1 The Discounted Stochastic Games.- 3.2 Linear Programming and the Discounted Stochastic Games.- 3.3 Modified Newton's Method and the Discounted Stochastic Games.- 3.4 Limiting Average Stochastic Games: The Issues.- 3.5 Zero-Sum Single-Controller Limiting Average Game.- 3.6 Application: The Travelling Inspector Model.- 3.7 Nonlinear Programming and Zero-Sum Stochastic Games.- 3.8 Nonlinear Programming and General-Sum Stochastic Games.- 3.9 Shapley's Theorem via Mathematical Programming.- 3.10 Bibliographic Notes.- 3.11 Problems.- II Existence, Structure and Applications.- 4 Summable Stochastic Games.- 4.0 Introduction.- 4.1 The Stochastic Game Model.- 4.2 Transient Stochastic Games.- 4.2.1 Stationary Strategies.- 4.2.2 Extension to Nonstationary Strategies.- 4.3 Discounted Stochastic Games.- 4.3.1 Introduction.- 4.3.2 Solutions of Discounted Stochastic Games.- 4.3.3 Structural Properties.- 4.3.4 The Limit Discount Equation.- 4.4 Positive Stochastic Games.- 4.5 Total Reward Stochastic Games.- 4.6 Nonzero-Sum Discounted Stochastic Games.- 4.6.1 Existence of Equilibrium Points.- 4.6.2 A Nonlinear Compementarity Problem.- 4.6.3 Perfect Equilibrium Points.- 4.7 Bibliographic Notes.- 4.8 Problems.- 5 Average Reward Stochastic Games.- 5.0 Introduction.- 5.1 Irreducible Stochastic Games.- 5.2 Existence of the Value.- 5.3 Stationary Strategies.- 5.4 Equilibrium Points.- 5.5 Bibliographic Notes.- 5.6 Problems.- 6 Applications and Special Classes of Stochastic Games.- 6.0 Introduction.- 6.1 Economic Competition and Stochastic Games.- 6.2 Inspection Problems and Single-Control Games.- 6.3 The Presidency Game and Switching-Control Games.- 6.4 Fishery Games and AR-AT Games.- 6.5 Applications of SER-SIT Games.- 6.6 Advertisement Models and Myopic Strategies.- 6.7 Spend and Save Games and the Weighted Reward Criterion.- 6.8 Bibliographic Notes.- 6.9 Problems.- Appendix G Matrix and Bimatrix Games and Mathematical Programming.- G.1 Introduction.- G.2 Matrix Game.- G.3 Linear Programming.- G.4 Bimatrix Games.- G.5 Mangasarian-Stone Algorithm for Bimatrix Games.- G.6 Bibliographic Notes.- Appendix H A Theorem of Hardy and Littlewood.- H.1 Introduction.- H.2 Preliminaries, Results and Examples.- H.3 Proof of the Hardy-Littlewood Theorem.- Appendix M Markov Chains.- M.1 Introduction.- M.2 Stochastic Matrix.- M.3 Invariant Distribution.- M.4 Limit Discounting.- M.5 The Fundamental Matrix.- M.6 Bibliographic Notes.- Appendix P Complex Varieties and the Limit Discount Equation.- P.1 Background.- P.2 Limit Discount Equation as a Set of Simultaneous Polynomials.- P.3 Algebraic and Analytic Varieties.- P.4 Solution of the Limit Discount Equation via Analytic Varieties.- References.

Role of television in adolescent women's body dissatisfaction and drive for thinness

Abstract: Objective Many authors have implicated the media's promotion of an unrealistically thin ideal for women as a major causal factor in the current high levels of body dissatisfaction and increasing incidence of eating disorders. The present study aimed to investigate the relationship between exposure to one medium, television, and body dissatisfaction and drive for thinness. Method: Questionnaires were administered to 94 adolescent women who reported how much and what television they had watched in the previous week. Body dissatisfaction and drive for thinness were also assessed. Results: Amount of television watched did not correlate with either body dissatisfaction or drive for thinness, but category of program did. Specifically, amount of time spent watching soaps, movies, and (negatively) sport predicted body dissatisfaction, and the watching of music videos predicted drive for thinness. Discussion: The results are consistent with sociocultural explanations for body dissatisfaction and for the emergence of eating disorders in young women. © 1996 by John Wiley & Sons, Inc.

Surface and Capillary Forces Affecting Air Bubble−Particle Interactions in Aqueous Electrolyte

Abstract: The interaction between hydrophilic silica particles and air bubbles in aqueous electrolyte has been studied by colloid probe atomic force microscopy. The interaction was found to be monotonically repulsive on approach. The silica surface was also hydrophobized by dehydroxylation and by treatment with octadecyltrichlorosilane (OTS). In these cases a repulsion was observed at long range with an attraction evident as the bubble−particle separation decreased. For a freshly prepared OTS−silica surface the intervening thin film rapidly collapsed, resulting in particle engulfment or establishment of a three-phase line. For an aged OTS−silica surface a stable film was formed which could be ruptured as the loading force was increased. In all cases adhesion resisted bubble−particle separation. This behavior was rationalized in terms of either attractive surface forces or capillary forces and contact angle hysteresis operating after formation of a three-phase line (TPL).

Long expected sponges from the neoproterozoic ediacara fauna of south australia

Abstract: ABsTRAC--New fossils from the Neoproterozoic Ediacara fauna of South Australia are interpreted as the oldest known hexactinellid sponges. They occur within the Ediacara Member of the Rawnsley Quartzite (Pound Subgroup) from several locations in the Flinders Ranges. The new genus, Palaeophragmodictya, is characterized by disc-shaped impressions preserving characteristic spicular networks and is reconstructed as a convex sponge with a peripheral frill and an oscular disc at the apex.

Concentration and pH dependence of skeletal muscle chloride channel ClC‐1.

Abstract: 1. The influence of Cl- concentration and pH on gating of the skeletal muscle Cl- channel, ClC-1, has been assessed using the voltage-clamp technique and the Sf-9 insect cell and Xenopus oocyte expression systems. 2. Hyperpolarization induces deactivating inward currents comprising a steady-state component and two exponentially decaying components, of which the faster is weakly voltage dependent and the slower strongly voltage dependent. 3. Open probability (Po) and kinetics depend on external but not internal Cl- concentration. 4. A point mutation, K585E, in human ClC-1, equivalent to a previously described mutation in the Torpedo electroplaque chloride channel, ClC-0, alters the I-V relationship and kinetics, but retains external Cl- dependence. 5. When external pH is reduced, the deactivating inward currents of ClC-1 are diminished without change in time constants while the steady-state component is enhanced. 6. In contrast, reduced internal pH slows deactivating current kinetics as its most immediately obvious action and the Po curve is shifted in the hyperpolarizing direction. Addition of internal benzoate at low internal pH counteracts both these effects. 7. A current activated by hyperpolarization can be revealed at an external pH of 5.5 in ClC-1, which in some ways resembles currents due to the slow gates of ClC-0. 8. Gating appears to be controlled by a Cl(-)-binding site accessible only from the exterior and, possibly, by modification of this site by external protonation. Intracellular hydroxyl ions strongly affect gating either allosterically or by direct binding and blocking of the pore, an action mimicked by intracellular benzoate.

Nursing documentation and nursing practice: a discourse analysis.

Abstract: Nursing documentation exists as a daily reality of nurses' work. It is interpreted by some as the evidence of nursing actions and dismissed by others as a misrepresentation of nursing care. This paper reports on a study of nursing documentation as nursing practice. The work of Foucault and discourse analysis provide a research design for examination of how written descriptions of patient events taken from patient case notes result from hegemonic influences that construct a knowledge and therefore a practice of nursing. Discourses as ways of understanding knowledge as language, social practices and power relations are used to identify how nursing documentation functions as a manifestation and ritual of power relations. A focus on body work and fragmented bodies provided details of nursing's participation in the discursive construction of the object patient and invisible nurse. It is through resistances to documentation that alternative knowledge of nursing exists.

Brand Equity and Market-Based Assets of Professional Service Firms

Abstract: The concept of brand equity has received most attention in the context of fast-moving-consumer-goods marketing yet the concept is just as, if not more, important to professional services marketers. This paper explains the distinct nature of market-based assets, such as brand equity, in professional service industries.

Day-time melatonin administration: Effects on core temperature and sleep onset latency

Abstract: Significant hypothermic and hypnotic effects have been reported for melatonin at a wide range of doses. It has been suggested that this decrease in core temperature (Tc) following melatonin administration may mediate the observed increase in sleepiness. To test this, melatonin was administered to young adults during the day, and the concurrent effects on Tc and sleep onset latency (SOL) were recorded. Sixteen healthy males received either a 5 mg oral formulation of melatonin or placebo at 14.00 hours. Core temperature was recorded continuously. Sleep onset latency to stage 1 (SOL1) and stage 2 (SOL2) were recorded using an hourly multiple sleep latency test (MSLT). Compared with placebo, melatonin significantly decreased Tc 1.5 h after administration for 6 h. Between 15.00 and 18.00 hours, the drop in Tc was associated with a concurrent decrease in SOL1 and SOL2. Following administration mean SOL1 and SOL2 were reduced by 40 and 25%, respectively. In this study, daytime melatonin administration produced a significant decrease in Tc with a corresponding decrease in SOL. Taken together, these data are not inconsistent with the suggestion that melatonin may facilitate sleep onset via a hypothermic effect. In addition, this study provides support for the idea that melatonin may play a role in regulating circadian and/or age-related variations in sleep/wake propensity. From a practical perspective, exogenous melatonin may be useful in the treatment of sleep disorders associated with increased nocturnal Tc.

Irradiation Effects During XPS Studies of Cu(II) Activation of Zinc Sulphide

Abstract: The surfaces of zinc sulphide particles after copper(II) activation at pH 9 have been studied by x-ray photoelectron spectroscopy The influence of x-ray irradiation time on the forms and intensities of the photoelectron signals from zinc sulphide particles activated at various copper coverages was investigated High binding energy components and satellites of the Cu 2p signals, characteristic of copper(II) hydroxide overlayers, reduced in intensity with increased x-ray exposure An associated reduction in the concentration of surface oxygen was also observed Differential charging analysis and curve fitting reveal the dehydration of Cu(OH) 2 to CuO, followed by photoreduction of CuO to Cu 2 O No evidence was found for x-ray irradiation enhancement of continued Cu activation of or diffusion into ZnS

Adhesion of Iron Oxide to Silica Studied by Atomic Force Microscopy

Abstract: The interaction of an iron oxide sphere with a silica flat immersed in a dilute electrolyte solution has been studied with an atomic force microscope using the colloid probe technique. The adhesion energy obtained from measurement of the pull-off force, as a function of ionic strength and pH, has been a particular focus. The pH range over which adhesion occurred correlated strongly with electrokinetic data, suggesting that an electrostatic mechanism was dominant. However, the magnitude of the adhesion was significantly less than that anticipated on the basis of the attractive van der Waals and electrostatic forces and the adhesion decreased with increasing ionic strength. These results may be qualitatively explained in terms of the roughness of component surfaces, which increases the effective separation at asperity contact. In addition the pull-off force was not found to be single-valued but dependent on the loading force prior to separation of the surfaces. The presence of a hydration or gel layer, giving rise to a strong short-range repulsion in the neighborhood of the contact points is implicated. These observations highlight deficiencies in currently accepted adhesion models for the description of nonideal, particularly rough, surfaces.

Surface Forces between Spherical ZnS Particles in Aqueous Electrolyte

Abstract: An atomic force microscope has been used to measure the forces of interaction between ZnS spheres in aqueous electrolyte. The ZnS surface, characterized by scanning electron microscopy, tapping mode atomic force microscopy, and gas adsorption, was found to be physically heterogeneous. The measured interaction behavior is not well described by conventional theory where interacting surfaces are assumed to be physically ideal. In particular the van der Waals attraction could not be measured at pHiep and elevated ionic strength, where the electrical repulsion between surfaces is minimal. In addition no short range repulsion that could be attributed to hydration was observed. If the range of a surface force is small compared to the roughness of the surface, then it may have little effect on particle interaction. In contrast only forces of long range compared to roughness, electrical and hydrophobic in this case, are directly measurable. The hydrophobic attraction which becomes evident at low pH was found to be...

A new model for generation-recombination in silicon depletion regions after neutron irradiation

Abstract: Deep level transient spectroscopy has been used to investigate defects in high resistivity silicon diodes after neutron irradiation. Three defects have been correlated with the leakage current. The leakage current in the diodes is found to be a factor of 50 to 600 greater than expected from standard Shockley-Read-Hall (SRH) theory for the observed defect-concentrations. The results can be explained by an enhancement factor due to intercentre transfer of charge between defects in close proximity to each other. It is proposed that a possible mechanism for this process is rapid, direct transfer between a deep donor state and a deep acceptor state. An unidentified defect is observed at E/sub C/-0.45/spl plusmn/0.02 eV which anneals at /spl sim/700/spl deg/C. This defect is correlated to excess leakage current in both diodes and charge coupled devices.

Ken and Barbie at life size

Abstract: There has been considerable discussion in both the scientific literature and general media concerning the appropriateness of the body shape and proportions of the Ken and Barbie dolls, the most popular dolls in modern history. The greatest concern has been of the possible influence that these, and other “cultural ideals” for body shape, may have on young children. However, these concerns have been based entirely on the subjective interpretation of how one perceives the body dimensions of the dolls relative to an adult size. We therefore used our skills in anthropometry and the rules of allometry to scale the dolls to an adult height to determine the dimensions that these dolls would assume at this adjusted size. These were compared to actual proportions of several representative adult groups of predominantly Anglo-Australian males and females. The critics have been justified in their opinions since both Barbie and Ken are thin relative to the reference samples. Barbie's mean girth z-score relative to a reference cross-section of the young adult population was −4.2. This indicates that the probability for such a body shape is less than 1 in 100,000. Ken is more realistic at about 1 in 50.

Assessing document relevance with run-time reconfigurable machines

Abstract: Free text database searching is a natural candidate for acceleration by run time reconfigurable custom computing machines. We describe a fully pipelined search machine architecture for scoring the relevance of textual documents against approximately 100 relevant target words, with provision for limited regular expression matching and error tolerance. An implementation on the SPACE custom computing platform indicates that throughput in the order of 20 megabytes per second is achievable on ALgotronix FPGAs if a locally synchronous design style is adopted and global communications minimized. Partial reconfiguration of the datapath at run time, in around 3 seconds, serves to maximize the density of data storage on the machine and correspondingly avoid costly input from the environment.

The hypothermic effect of melatonin on core body temperature : Is more better ?

Abstract: Recent studies have shown that melatonin is both hypnotic and hypothermic at physiological levels. Indeed, the hypnotic effect may be mediated via the hypothermic action. If this is the case, it is important to explore the dose-response relationships for the thermoregulatory effects of melatonin. Four groups of eight healthy adults (n = 32), aged between 18 and 38, each underwent two 12-hr bedrest protocols in which core body temperature (CT) and plasma melatonin levels were measured concurrently between 0800 and 2000 hr. For each group, subjects ingested either sucrose placebo or a 0.1, 0.5, 1.0, or 5.0 mg melatonin capsule at 1600 hr in a double-blind counterbalanced cross-over design. Melatonin was absorbed rapidly, with peak levels being reached after 1 hr at all dose levels. Mean peak plasma melatonin levels increased from physiological to pharmacological levels in a dose-dependent manner. Elimination for all dose levels was rapid, with mean plasma half-lives between 33 and 47 min. At the lower doses the mean drop in CT was between 0.05 and 0.15 degrees C and took between 2 and 3 hr. At the higher doses (1.0 and 5.0 mg), CT fell by 0.25-0.3 degrees C within 30-60 min following ingestion and at the highest dose (5 mg) remained suppressed for the duration of the study. While the magnitude and duration of the drop increased in what appeared to be a dose-dependent manner, it is unlikely that this relationship reflects a simple dose-response curve. There was considerable variability in plasma profiles following administration, particularly at the two lowest doses (0.1 and 0.5 mg). The lower mean drop in CT probably reflects the lower proportion of subjects achieving physiological plasma levels, and therefore a hypothermic effect, at the two lowest doses. If melatonin is to be used to improve sleep onset and maintenance by lowering CT, doses between 1.0 and 5.0 mg appear to be the lowest that produce a consistent drop in CT across all subjects.

Acute lobar atelectasis: A comparison of five physiotherapy regimens

Abstract: Thirty-five patients with acute lobar atelectasis were allocated to one of five treatment groups (seven patients per group). Intubated patients received manual hyperinflation and suction with or without the addition of postural drainage or modified postural drainage and chest wall vibrations. For the non-intubated patients, deep breathing, coughing and huffing replaced the techniques of manual hyperinflation and suction. Frequency of treatment ranged from hourly for 6 h for four groups, to one treatment only for the fifth group. The results suggest that modified postural drainage is an effective additional component to manual hyperinflation and suction performed hourly for 6 h. The addition of chest wall vibrations to this treatment regimen did not further enhance the response to treatment, nor did the use of traditional postural drainage positions. There was evidence that hourly treatment for 6 h using modified postural drainage, manual hyperinflation and suction was more effective than one treatment only.

Understanding Traffic Systems: Data Analysis and Presentation

Abstract: Contents: Introduction: Introduction and context The traffic analysis process. Basic Traffic Theory: Basic traffic flow theory Theories of interrupted traffic flow Theories of area-wide traffic flow. Data Capture: Principles of survey planning and management Experimental design and sample theory Vehicle counting and classification surveys Traffic condition data Environmental impacts. Traffic Studies: Intersection studies Origin-destination and route choice studies Traffic generation and parking studies Road safety studies. Data Analysis and Modelling: From data to information Statistical analysis Statistical modelling. Appendix A: Statistical tables Appendix B: Database of vehicle speeds on residential streets References Index.

Pharmacodynamics and pharmacokinetics of the profens: enantioselectivity, clinical implications, and special reference to S(+)-ibuprofen.

Abstract: The 2-arylpropionic acid derivatives, or "profens," are an important class of nonsteroidal antiinflammatory drugs (NSAIDs) that have been in clinical use for almost 30 years. Widely used members of this drug class include naproxen, ibuprofen, ketoprofen, flurbiprofen, and tiaprofenic acid. With the exception of S-naproxen, the profens have until recently been used clinically as racemic agents, and a "single enantiomer versus racemate" debate has emerged. Several important issues should be considered in the debate: the antinociceptive activity of the R-enantiomer of at least one profen (flurbiprofen), the possible role of cyclooxygenase (COX)-independent properties of the R-enantiomers in the gastrointestinal toxicity of the racemates, the increase in the formation of potentially immunogenic drug-protein adducts when racemates are administered, and the likelihood that the use of racemates increases the propensity of the profens to alter the pharmacokinetics of other drugs. This review will demonstrate how the use of individual enantiomers can improve understanding of the mechanisms by which the profens elicit their biologic effects.