Showing papers by "Flinders University published in 1995"

Accurate nucleon-nucleon potential with charge-independence breaking

Abstract: The authors present a new high-quality nucleon-nucleon potential with explicit charge dependence and charge asymmetry, which they designate Argonne {upsilon}{sub 18}. The model has a charge-independent part with fourteen operator components that is an updated version of the Argonne {upsilon}{sub 14} potential. Three additional charge-dependent and one charge-asymmetric operators are added, along with a complete electromagnetic interaction. The potential has been fit directly to the Nijmegen pp and np scattering data base, low-energy nn scattering parameters, and deuteron binding energy. With 40 adjustable parameters it gives a {chi}{sup 2} per datum of 1.09 for 4,301 pp and np data in the range 0--350 MeV.

Predictors of 30-Day Mortality in the Era of Reperfusion for Acute Myocardial Infarction Results From an International Trial of 41 021 Patients

Abstract: Background Despite remarkable advances in the treatment of acute myocardial infarction, substantial early patient mortality remains. Appropriate choices among alternative therapies and the use of clinical resources depend on an estimate of the patient's risk. Individual patients reflect a combination of clinical features that influence prognosis, and these factors must be appropriately weighted to produce an accurate assessment of risk. Prior studies to define prognosis either were performed before widespread use of thrombolysis or were limited in sample size or spectrum of data. Using the large population of the GUSTO-I trial, we performed a comprehensive analysis of relations between baseline clinical data and 30-day mortality and developed a multivariable statistical model for risk assessment in candidates for thrombolytic therapy. Methods and Results For the 41 021 patients enrolled in GUSTO-I, a randomized trial of four thrombolytic strategies, relations between clinical descriptors routinely collected at initial presentation, and death within 30 days (which occurred in 7% of the population) were examined with both univariable and multivariable analyses. Variables studied included demographics, history and risk factors, presenting characteristics, and treatment assignment. Risk modeling was performed with logistic multiple regression and validated with bootstrapping techniques. Multivariable analysis identified age as the most significant factor influencing 30-day mortality, with rates of 1.1% in the youngest decile ( 75 (adjusted chi(2)=717, P<.0001). Other factors most significantly associated with increased mortality were lower systolic blood pressure (chi(2)=550, P<.0001), higher Killip class (chi(2)=350, P<.0001), elevated heart rate (chi(2)=275, P<.0001), and anterior infarction (chi(2)=143, P<.0001). Together, these five characteristics contained 90% of the prognostic information in the baseline clinical data. Other significant though less important factors included previous myocardial infarction, height, time to treatment, diabetes, weight, smoking status, type of thrombolytic, previous bypass surgery, hypertension, and prior cerebrovascular disease. Combining prognostic variables through logistic regression, we produced a validated model that stratified patient risk and accurately estimated the likelihood of death. Conclusions The clinical determinants of mortality in patients treated with thrombolytic therapy within 6 hours of symptom onset are multifactorial and the relations complex. Although a few variables contain most of the prognostic information, many others contribute additional independent prognostic information. Through consideration of multiple characteristics, including age, medical history, physiological significance of the infarction, and medical treatment, the prognosis of an individual patient can be accurately estimated.

Interpretive approaches in nursing research: the influence of Husserl and Heidegger

Abstract: This paper aims to throw some light on Husserlian phenomenology and Heideggerian hermeneutics, and to discuss their influences and applicability to the nursing research agenda. There are definite distinctions between Husserlian transcendental phenomenology and Heideggerian hermeneutic phenomenology and these distinctions have implications for the methodology employed. These traditions are discussed with respect to some fundamental research issues: the philosophical perspectives of the traditions and the notion that data that result from the inquiry are created by the interaction between researcher and researched. The central recommendation in this paper is that nurse researchers appraise the philosophical underpinnings of the methodologies they pursue.

Immunocytochemical quantitation of human immunodeficiency virus in the brain: Correlations with dementia

Abstract: The pathogenesis of human immunodeficiency virus (HIV)-associated dementia is unclear, and the underlying pathological substrate has been a matter of debate. In a prospectively clinically characterized population of acquired immunodeficiency syndrome (AIDS) patients we investigated the relationship between the clinical syndrome of HIV-associated dementia and the presence and relative quantity of immunocytochemical markers for HIV-1 (gp41 antibody), and for macrophages and microglia (HAM-56 antibody). Sections from the basal ganglia and frontal lobes from the brains of 51 patients were studied, and the data were stratified for severity of dementia (16 nondemented, 12 mildly demented, 23 severely demented), rate of dementia progression, duration of AIDS, use of antiretrovirals, and several other demographic features. We found a highly significant correlation between the degree of macrophage staining and the severity of dementia but only a borderline correlation between the presence and amount of gp41-positive cells and dementia. Several nondemented patients showed abundant gp41 immunoreactivity, and some severely demented showed little to no gp41 immunoreactivity. Other correlations with the immunostaining data, including antiretroviral use, were not significant. We conclude that the presence of macrophages and microglia is a better correlate with HIV-associated dementia than is the presence and amount of HIV-infected cells in the brain. These data support the concept that the pathogenesis of HIV-associated dementia is likely due to indirect effects of HIV infection of the brain, possibly through the actions of macrophages and microglia.

A Population-Based Assessment of the Impact and Burden of Caregiving for Long-term Stroke Survivors

Abstract: Background and Purpose Little attention has been focused on the demands on caregivers in stroke outcome research. A major aim of this study was to identify factors in patients associated with emotional distress in caregivers 1 year after stroke. Methods One-year stroke survivors with residual handicap (defined by the Oxford Handicap Scale) and their chief caregivers were interviewed as part of the follow-up activities for patients (n=492) registered with the Perth Community Stroke Study. We assessed emotional distress in caregivers using the Hospital Anxiety and Depression Scale and the 28-item General Health Questionnaire. Appropriate sections of the Social Behaviour Assessment Schedule were used to assess the patient’s behavior and the impact on the caregiver’s life. Other aspects of the patient’s functional state were assessed with the Barthel Index, the Mini-Mental State Examination, the Frenchay Activities Index, and the Psychiatric Assessment Schedule (at 4 months after stroke). Results Of 241 patie...

Image and mind : film, philosophy and cognitive science

Abstract: This is a book about the nature of film: about the nature of moving images, about the viewer's relation to film, and about the kinds of narrative that film is capable of presenting. It represents a very decisive break with the semiotic and psychoanalytic theories of film which have dominated discussion. The central thesis is that film is essentially a pictorial medium and that the movement of film images is real rather than illusory. A general theory of pictorial representation is presented, which insists on the realism of pictures and the impossibility of assimilating them to language. It criticizes attempts to explain the psychology of film viewing in terms of the viewer's imaginary occupation of a position within the world of film. On the contrary, film viewing is nearly always impersonal.

Calculation of electron-helium scattering.

Abstract: We present the convergent close-coupling theory for the calculation of electron-helium scattering. We demonstrate its applicability at a range of projectile energies of 1.5 to 500 eV to scattering from the ground state to n\ensuremath{\le}3 states. Generally, good agreement with experiment is obtained with the available differential, integrated, ionization, and total cross sections, as well as with the electron-impact coherence parameters up to and including the 3 $^{3}$D-state excitation. This agreement is shown to be overall the best of the currently used electron-helium scattering theories. On occasion, some significant discrepancies with experiment are observed, particularly for the triplet-state excitations.

A Meta-Analysis on the Efficacy of Epidural Corticosteroids in the Treatment of Sciatica:

Abstract: The efficacy of epidural corticosteroids in the treatment of sciatica was investigated by meta-analysis of all randomized controlled trials. Eleven suitable trials of good quality were identified involving a total of 907 patients. The use of epidural (caudal or lumbar) steroid in the short-term (up to 60 days) increased the odds ratio (OR) of pain relief ( > 75% improvement) to 2.61 (95% CI 1.90-3.77) when compared with placebo. Despite some variations in trial characteristics there was little evidence of significant heterogeneity (P = 0.07). When the trials were analysed for near or total relief of pain in the short-term the OR is 2.79 (95% CI 1.92-4.06), for heterogeneity (P = 0.07). For longterm relief of pain (up to 12 months) the OR is 1.87 (95% CI 1.31-2.68). Efficacy is independent of the route of injection; for caudal epidural steroid the OR is 3.80 (95% CI 1.36-10.6) and for the lumbar epidural steroid 2.43 (95% CI 1.77-3.74). Adverse events included dural tap (2.5%), transient headache (2.3%) and a transient increase in pain (1.9%). There were no reported longterm adverse events. In conclusion we present quantitative evidence from meta-analysis of pooled data from randomized trials that epidural administration of corticosteroids is effective in the management of lumbosacral radicular pain.

Learning internal representations

Abstract: Probably the most important problem in machine learning is the preliminary biasing of a learner's hypothesis space so that it is small enough to ensure good generalisation from reasonable training sets, yet large enough that it contains a good solution to the problem being learnt. In this paper a mechanism for {\em automatically} learning or biasing the learner's hypothesis space is introduced. It works by first learning an appropriate {\em internal representation} for a learning environment and then using that representation to bias the learner's hypothesis space for the learning of future tasks drawn from the same environment. An internal representation must be learnt by sampling from {\em many similar tasks}, not just a single task as occurs in ordinary machine learning. It is proved that the number of examples $m$ {\em per task} required to ensure good generalisation from a representation learner obeys $m = O(a+b/n)$ where $n$ is the number of tasks being learnt and $a$ and $b$ are constants. If the tasks are learnt independently ({\em i.e.} without a common representation) then $m=O(a+b)$. It is argued that for learning environments such as speech and character recognition $b\gg a$ and hence representation learning in these environments can potentially yield a drastic reduction in the number of examples required per task. It is also proved that if $n = O(b)$ (with $m=O(a+b/n)$) then the representation learnt will be good for learning novel tasks from the same environment, and that the number of examples required to generalise well on a novel task will be reduced to $O(a)$ (as opposed to $O(a+b)$ if no representation is used). It is shown that gradient descent can be used to train neural network representations and experiment results are reported providing strong qualitative support for the theoretical results.

An evaluation of sequence tagged microsatellite site markers for genetic analysis within Citrus and related species

Abstract: Microsatellites, also called sequence tagged microsatellite sites (STMSs), have become important markers for genome analysis but are currently little studied in plants. To assess the value of STMSs for analysis within the Citrus plant species, two example STMSs were isolated from an intergeneric cross between rangpur lime (Citrus x limonia Osbeck) and trifoliate orange (Poncirus trifoliata (L.) Raf.). Unique flanking primers were constructed for polymerase chain reaction amplification both within the test cross and across a broad range of citrus and related species. Both loci showed length variation between test cross parents with alleles segregating in a Mendelian fashion to progeny. Amplification across species showed the STMS flanking primers to be conserved in every genome tested. The traits of polymorphism, inheritance, and conservation across species mean that STMS markers are ideal for genome mapping within Citrus, which contains high levels of genetic variability.

How successful is corneal transplantation? A report from the Australian corneal graft register

Abstract: Corneal graft outcome was assessed within a large, prospectively collected database of 4499 records. Penetrating corneal graft survival was 91% at 1 year, 72% at 5 years and 69% at 7 years. The three most common indications for graft were keratoconus (30%), bullous keratopathy (25%) and failed previous graft (18%); the three most common causes of graft failure were rejection (34%), infection (18%) and glaucoma (9%). The vast majority of grafts were performed for improved visual acuity. About four-fifths of recipients achieved at least one line of better acuity on the Snellen chart post-operatively; of the remainder with unchanged or worse acuity, only 21% had failed grafts. Overall, 43% of recipients achieved a best corrected Snellen acuity of 6/12 or better, 52% achieved 6/18 or better, and 20% had acuitities of less than 6/60. Reasons for poor post-operative acuity (recorded as less than 6/60) included graft failure (41%) and comorbidities in the grafted eye (43%). A number of risk factors for graft failure were examined: in most instances, there was little room for decision-making or expert intervention.

Design of an Internet‐based system for remote Dutch auctions

Abstract: Outlines the principle of the Dutch auction, whereby the price begins at a high level and decreases by steps until a bid is made. Describes an integrated hardware and software system which uses Internet communications to enable remotely created bidders to participate in real‐time Dutch auctions and which meets the stringent requirement that synchrony be maintained among bidders’ terminals to ensure that each bidder has a fair chance to bid at the current offer price. Defines the principal functions of the system and characterizes its available resources. Illustrates implementation using a prototype design. Pays particular attention to bidder terminal synchronization, bidder authentication, and auction client security. Includes the possibility of a system variant using ISDN interconnect and PC‐based bidders’ terminals.

A channel-like transporter for NH 4 + on the symbiotic interface of N 2 -fixing plants

Abstract: SYMBIOSIS with nitrogen-fixing bacteria (rhizobia) allows legumes to survive in nitrogen-poor soils. The nitrogen-fixing bacteroids are found inside root nodule cells within the symbiosome, an organelle bounded by the peribacteroid membrane1. Across this membrane the plant receives fixed nitrogen in exchange for reduced carbon2. It has been assumed that fixed nitrogen is released from the symbiosome as either NH3 or NH4+ , but until now the transport mechanism was unknown3–5. We report here the use of patch-clamp techniques to show, in membrane patches on isolated symbiosomes, smoothly activating currents that are passive and equivalent to the influx of cations to the plant cytoplasm. The currents are largest with NH4+ as the cation at physiological concentration and they are blocked by calcium ions on the bacteroid side of the membrane. The characteristics of the currents are more like those of a channel than of carrier-mediated transport. In vivo nitrogen would move passively as NH4+ to the cytoplasm upon energization of the membrane and calcium ions may be involved in regulation of the flux.

The Experiences of International and Local Students at Three Australian Universities.

Abstract: In 1992 international fee‐paying and local students currently enrolled at the three tertiary institutions in South Australia were surveyed by a common questionnaire on students’ study‐related and personal experiences, and issues related to students’ choice and subsequent evaluation of their institution. The breadth of the student sample and the comparative data the questionnaire generated present an overarching view of the experiences and evaluations of a diverse range of university students. The results of the survey show that while international students experience more problems, and experience them to a more serious degree than their Australian counterparts, the nature of the issues which are of most concern are generally shared. These are concerns about financial issues such as access to Austudy for local students, and the level of fees for international students and the ability to find part‐time work for both groups. The other broad group of issues of concern was study related: workload, fea...

Characterisation of CYP3A gene subfamily expression in human gastrointestinal tissues.

Abstract: The human CYP3A subfamily is of interest due to its multiplicity, activity toward known carcinogens, and extrahepatic expression. In situ hybridisation analysis of formalin fixed, routinely processed biopsy specimens was used to localise CYP3A mRNA in human gastrointestinal tissues from several individuals. CYP3A mRNA is abundant in human liver and in mucosal epithelial cells of all segments of the human small intestine. RNA blot analyses showed that the mRNA species observed in most livers and in human small intestine represent CYP3A3/3A4 transcripts. This was confirmed at the protein level by immunoblot comparison of small intestine microsomes to in vitro expressed CYP3A4 and CYP3A5 proteins. In liver and small intestine, CYP3A mRNA is not uniformly distributed, with grain density highest in cells within the respective non-proliferative compartments. CYP3A mRNA was also observed in human oesophagus and colon. RNA blot analysis of multiple colons showed heterogeneity in the CYP3A mRNAs present. Two CYP3A mRNAs (CYP3A3/3A4 and CYP3A5) were detected in colon samples from several individuals. In addition to those localisation studies, the capacity of expressed CYP3A4 and CYP3A5 to activate the dietary heterocyclic amine MeIQ in the presence of alpha-naphthoflavone was shown. These results show that there is considerable heterogeneity in the expression of the CYP3A subfamily in human gastrointestinal tissues.

Characterization of cobalt Fischer-Tropsch catalysts I. Unpromoted cobalt-silica gel catalysts

Abstract: The effect of preparation conditions on cobalt-silica gel catalysts has been investigated by temperature-programmed reduction, differential thermal analysis, X-ray photoelectron spectroscopy, and magnetic susceptibility measurements. The results have been correlated with the performance of the catalysts for the conversion of syngas. It has been found that active Fischer-Tropsch (F-T) cobalt catalysts can be partially or totally reduced to the metal phase during activation. However, reducibility of the catalysts is a necessary but not sufficient characteristic in ensuring good activity. The pH of the impregnating solution influences surface charge and solubility of silica gel. Consequently, the physical and chemical properties of the cobalt species on the surface of silica gel are strongly affected by this parameter. At pH

Adolescent suicide, depression and family dysfunction

Abstract: This study investigated associations between adolescents' perceptions of their family dynamics (McMaster Family Assessment Device, FAD) and depression, suicide thoughts and attempts. High school students (mean age 15.2 years) completed self-report questionnaires including the Beck Depression Inventory (BDI), the FAD, questions about suicidal thoughts, plans and attempts, deliberate self harm, and selected life experiences. Univariate analysis showed that family dysfunction measured on the FAD is associated with thinking and planning suicide, deliberate self harm, suicide attempts, as well as severe depression (BDI ≥ 222). Despite this, stepwise regression indicated that family dysfunction influences suicide behaviors indirectly through other variables such as depression. The FAD is recommended as a useful addition to questionnaires seeking to identify vulnerability to both depression and adolescent attempted suicide in early detection studies.

The 'pressures to change' approach to working with the partners of heavy drinkers

Abstract: The 'Pressures to Change' approach to working with the partners of drinkers is a structured procedure for promoting change in resistant drinkers. In this study 22 women and one man were randomly allocated to two treatment conditions and one no-treatment waiting list control condition in an experimental evaluation of the procedure. Group 1 was treated individually and Group 2 was treated as a group. Almost two-thirds of the drinking partners of clients in treatment made a significant move towards change, compared with none of the drinkers in the waiting list control condition.

Understanding the small enterprise financial objective function

Abstract: This paper presents views on the small enterprise financial objective function that are sympathetic to existing financial thought, but which capture complexities arising in small enterprises that frequently receive minimal attention in the mainstream finance literature. It is argued that the small enterprise financial objective function should reflect the kinds of enterprise-specific risk that typically exist in small enterprises arising from liquidity, diversification, transferability, flexibility, control, and accountability considerations. A conceptualization of the small enterprise financial objective function by extension of conventional utility theory is presented. It is believed the resulting utility function holds promise as an explanatory framework for financial behavior in small enterprises in that it provides valuable insights into owner-manager decision making and small enterprise development. Consideration is also given to asset pricing model, which consequently might be used in small enterpr...

Comparison of the suppressive effects of interleukin-10 and interleukin-4 on synovial fluid macrophages and blood monocytes from patients with inflammatory arthritis.

Abstract: This study determined the potential capacity of interleukin-10 (IL-10), compared with IL-4, to control the production of tumour necrosis factor-alpha (TNF-alpha), IL-1 beta and IL-1 receptor antagonist (IL-1ra) and the expression of major histocompatibility complex (MHC) class II antigens by monocytes/macrophages isolated from synovial fluid of patients with rheumatoid or other forms of chronic inflammatory arthritis Mononuclear cells were isolated from synovial fluid and peripheral blood and incubated with or without lipopolysaccharide (LPS), and with or without IL-10 (100 U/ml, 10 ng/ml) or IL-4 (10 ng/ml) for 22 hr TNF-alpha, IL-1 beta and IL-1ra levels were measured by enzyme-linked immunosorbent assay (ELISA) in the culture supernatants, and MHC class II expression was examined on the monocytes/macrophages by flow cytometry IL-10, unlike IL-4, decreased TNF-alpha production by LPS-stimulated synovial fluid cells to the same extent as by LPS-stimulated peripheral blood cells from the same patients IL-10 and IL-4 suppressed equally IL-1 beta production by the same cells However, only IL-4 significantly increased IL-1ra production by synovial fluid mononuclear cells Synovial fluid cells expressed increased levels of MHC class II antigen, and these levels were not as efficiently suppressed by IL-10 as they were for peripheral blood cells Because IL-10 and IL-4 differentially regulate TNF-alpha and IL-1ra production by synovial fluid mononuclear cells, selective use of either IL-10 or IL-4 in the treatment of chronic inflammatory conditions will depend on whether TNF-alpha or IL-1, respectively, is established as primarily responsible for the maintenance of the chronic inflammatory condition

Do Explanations of Absenteeism Differ for Men and Women

Abstract: Despite the consistent finding in the absence literature that women tend to be absent more often than men, little attention has been paid to whether the process of absence differs by sex. This issue is examined using data collected from 1401 Australian employees from 61 different workplaces. Hypotheses suggest that the predictive ability of job satisfaction, age, commuting time, family responsibilities, stressful life events and shift work on absence behavior differs for men and women. To test these hypotheses, a multivariate model is developed and estimated. The results indicate that there are structural differences in the absence behavior of men and women, requiring the estimation of models separately for each sex. Moreover, strong support for all but one of the hypotheses is found. These results show the critical importance of considering the sex of employees when developing explanatory models of absence.

2nd World Congress of Herpetology

Abstract: A population of the sleepy lizard, Tiliqua rugosa, near Mt Mary, South Australia, was surveyed by random encounter captures along 42 km of transects over a 10 year period from 1982 to 1991. Population size, estimated by the Jolly-Seber method, was lowest (724 adults) following the 1982/1983 drought, but then increased to a plateau (1500-1600 adults) which was maintained for 5 years. Densities in each 1 km segment of the transects varied from 0.3 to 5.5 lizards per hectare. Adjacent segments of the transects varied more than two-fold in lizard numbers, and those differences were consistent over time. Over all years, an estimated 16% of juveniles survived their first year, 42% of those survived a second year, and 62% of those survived a third year. By the third year some juveniles had reached adult size, although others took more than 5 years to mature. The annual survival of adults of all ages was 80-90%, whereas only 4% of juveniles reached adulthood. Cars killed an average of 3% of the adult population each year, and were a major source of mortality. To sustain stable populations adults must live 20-50 years. This long-lived species has a population structure governed by low recruitment, but long survival of established adults. It differs from the rapid turnover dynamics reported for many other lizard species.

The Adelaide Activities Profile: a measure of the life-style activities of elderly people.

Abstract: A new instrument for the measurement of life-style activities of the elderly is described. The Adelaide Activities Profile (AAP) was developed in response to the shortcomings of the Frenchay Activities Index. The AAP was validated on a random sample of 1799 people aged 70 years and over, living outside of institutional care. Principal components factor analysis revealed four consistent factors from which four scales were derived; these scales were named domestic chores, household maintenance, service to others, and social activities. Analyses demonstrated the construct validity of the four life-style scales by showing them to be differentially sensitive to a range of domestic, health and social circumstances. It was concluded that the distinct and meaningful clusters of activities represented by the AAP scales should have broad application as health and social indicators.

A Biological Basis for Instantaneous Centres of Rotation of the Vertebral Column

Abstract: The instantaneous centre of rotation has proven to be a useful parameter of vertebral motion. The normal location of instantaneous centres has been determined in cadavers and in normal volunteers for the cervical, thoracic and lumbar spines, and abnormal location of centres has been shown to correlate with spinal pain. However, to date, an instantaneous centre has constituted no more than a convenient mathematical summary of vertebral kinematics. It has defied resolution into biologically meaningful parameters. This study offers a novel model of vertebral motion in which the instantaneous centre of rotation can be shown to be a function of the location of the centre of reaction of a vertebra, and the intrinsic rotation and translation it undergoes. These parameters are strictly linked by equations that determine the location of an axis of rotation. These equations allow aberrations in the location of an axis to be interpreted in terms of the anatomical and pathological factors that affect the centre of reaction of the vertebra and the rotation and translation it undergoes.