Showing papers by "University of Sydney published in 1986"

Health Promotion Glossary

Abstract: The first edition of this health promotion glossary of terms was published by the World Health Organization (WHO) in 1986 as a guide to readers of WHO documents and publications. It met a useful purpose in clarifying the meaning and relationship between the many terms which were not in common usage at that time. This first edition of the glossary has been translated into several languages (French, Spanish, Russian, Japanese and Italian), and the terms defined have been widely used both within and outside WHO. The glossary was adapted and republished in German in 1990. Much has happened since the publication of the glossary a decade ago. Most notably, in October 1986 the First International Conference on Health Promotion was held in Ottawa, Canada, producing what is now widely known as the Ottawa Charter for Health Promotion. This conference was followed by others which explored the major themes of the Ottawa Charter on healthy public policy (in Adelaide, 1988), and on supportive environments for health (in Sundsvall, 1991). These conferences have added greatly to our understanding of health promotion strategies and their practical application, as well as more fully accounting for issues of relevance to developing countries. This was taken a step further at the 4th International Conference on Health PromotionÐNew Players for a New Era: Leading Health Promotion into the 21st Century, which was held in Jakarta, Indonesia in July 1997. Several WHO programmes and projects have been developed and implemented which have sought to translate health promotion concepts and strategies into practical action. These include: the `Healthy Cities, Villages, Municipalities' and `Healthy Islands' projects; the networks of `Health Promoting Schools' and `Health Promoting Hospitals'; the `Healthy Marketplaces and `Health Promoting Workplaces' projects; as well as WHO action plans on alcohol and tobacco, active living and healthy ageing. Recent developments in health systems around the world have given new prominence to health promotion approaches. The increasing focus on health outcomes reconfirms the priority placed on investment in the determinants of health through health promotion. Continually asking the question `where is health created?' links health promotion to two major reform debates: the formulation of new public health strategies, and the need to re-orient health services. The foresight shown in the Ottawa Charter has been adopted by many countries and organizations around the worldÐa process which was taken one step further through the 4th International Conference on Health Promotion in Jakarta, July 1997. This Conference adopted the Jakarta Declaration on Leading Health Promotion into the 21st Century. A number of terms that are HEALTH PROMOTION INTERNATIONAL Vol. 13, No. 4 # Oxford University Press 1998 Printed in Great Britain

On the essential work of ductile fracture in polymers

Abstract: The essential work of fracture concept has been extended to cover ductile tearing of polymeric materials that neck before fracture. It is shown that the plane stress specific essential fracture work (we) can be obtained from deeply edge-notched tension specimens, containing either single or double notches, by extrapolating the straight line relationship between the total specific fracture work (wf) and ligament length (l) to zero ligament. In this way, specific essential fracture works have been obtained for nylon 66 and two polyethylenes. It seems that weis a material property for a given sheet thickness being independent of specimen geometry. The straight line relationship between wfand l breaks down when the ligament length to sheet thickness ratio is less than about three, since the fracture data fall in the plane stress-plane strain transition region. However, a plane strain specific essential fracture work can still be obtained by extrapolating the least squares curve of the data to zero ligament provided the thickness satisfies plane strain condition. If this condition is not satisfied a near plane strain value is obtained which is dependent upon thickness. This method is also appropriate for ductile polymers like the rubber modified polystyrenes that craze rather than neck.

Crack growth resistance curves in strain-softening materials

Abstract: A theoretical model has been developed for the crack growth resistance ( K R ) curves in strain-softening materials with power law softening stress (σ)-crack opening displacement (δ) relationships. Both exact and approximate solution methods have been used to calculate K R curves for a fibre cement composite in a double-cantilever-beam (DCB) geometry. There is good agreement between these two solutions. When the crack growth is normalized with respect to the saturated softening (or fibre bridging) zone there is an almost unique K R curve which is independent of specimen geometry and initial crack length. The effects of the softening index ( n ) of the power law σ-δ relationship on the shapes, saturated softening zone lengths and plateau values of the K R curves are also studied.

Hyperthermia as a teratogen: A review of experimental studies and their clinical significance

Abstract: Although hyperthermia is teratogenic in birds, all the common laboratory animals, farm animals, and primates and satisfies defined criteria as a teratogen, its study as a human teratogen has been neglected. Homeothermic animals, including humans, can experience body temperature elevations induced by febrile infections, heavy exercise and hot environments which exceed the thresholds (1.5-2.5 degrees C elevation) which are known to cause a syndrome of embryonic resorptions, abortions, and malformations in experimental animals. Hyperthermia is particularly damaging to the central nervous system, and if a threshold exposure occurs at the appropriate stages of embryonic development, exencephaly, anencephaly, encephalocoele, micrencephaly, microphthalmia, neurogenic talipes, and arthrogryposis can be produced in a high proportion of exposed embryos, the incidence and type of defect depending on the species and strain within species, the stage of development, and the severity of hyperthermic exposure. Other defects which can be induced experimentally include exomphalos, hypoplasia of toes and teeth, renal agenesis, vertebral anomalies, maxillary hypoplasia, facial clefting, cataract, coloboma, and heart and vascular defects. Proliferating cells are particularly sensitive to temperature elevations, resulting in arrest of mitotic activity and immediate death of cells in mitosis with threshold elevations (1.5-2.5 degrees C) and delayed death of cells probably in S phase with higher elevations (3.5 degrees C). In general, lower temperature elevations (2.5 degrees C) require longer durations of elevation to cause defects than a simple spike at a higher elevation (4.5 degrees C). The death of cells is largely confined to the brain and in the day 21 guinea pig embryo to the alar regions of the brain. Cell death probably accounts for most of the defects in the central nervous system, but microvascular disturbances leading to leakage, oedema and haemorrhage, placental necrosis, and infarction are other known effects of hyperthermia; and these are probably involved in the pathogenesis of many defects of the heart, limbs, kidneys, and body wall. Recent experiments have demonstrated protection of rat embryos in culture against a known teratogenic exposure by a brief nonteratogenic exposure given at least 15 min earlier. This protection is associated with the synthesis of heat-shock proteins, and temporary arrest of the cell proliferative cycle. Hyperthermia appears to be capable of causing congenital defects in all species and may act alone or synergistically with other agents.(ABSTRACT TRUNCATED AT 400 WORDS)

Food availability affects growth in a coral reef fish

Abstract: Pomacentrus amboinensis is common on small patch reefs within One Tree Lagoon (Great Barrier Reef), where it preferentially settles onto deep reefs. A preliminary experiment, in which juveniles were transplanted to identical reef structures at two sites, within two depth strata, indicated that juvenile growth and survivorship were better in deeper water. The hypothesis that this difference was due to food availability was tested by a supplemental feeding experiment, carried out at another two randomly chosen sites, within the same two depth strata. Fish were fed each day over a one month period, during which no mortality was observed. The growth rates of juveniles were markedly higher on all food-supplemented reefs, when compared to controls. Growth differed between depth strata, but there was no interaction between the food x depth factors, which would have suggested a greater effect of food supplementation in either habitat. Thus, although the difference between depths cannot be attributed to food availability, the results have a more general significance. Food appears to be a limiting resource (in terms of growth) in both the marginal shallow habitat, and the more suitable deeper habitat.

Buckling of thin flat-walled structures by a spline finite strip method

Abstract: A method of buckling analysis of thin flat-walled structures of finite length subjected to longitudinal compression and bending, transverse compression as well as shear is described. The analysis uses the spline finite strip method and allows for boundary conditions other than simply supported ends as required in the semi-analytical finite strip method of buckling analysis. Convergence studies with increasing numbers of section knots are described for plates in compression, bending and shear, and for long columns with different support conditions subjected to compression. A buckling analysis of a stiffened plate subjected to compression and shear is compared with results from a finite element analysis.

Isotretinoin embryopathy and the cranial neural crest: an in vivo and in vitro study

Abstract: Severe congenital malformations have been associated with the inadvertant use in early pregnancy of a new dermatological drug, isotretinoin. We present proposals for the pathogenesis of this embryopathy based on the study of animal models. The characteristic malformations of the face, thymus, and great vessels were induced in mice by prenatal exposure to the drug during the early somite stages of development. From histological examination of mouse embryos it was shown that the drug directly interferes with the development of cranial neural crest cells. Subsequent deficiency of crest cell-derived mesenchyme adequately explains most of the observed malformations. Rat embryo culture studies showed that, when used at concentrations of 500 ng/ml, both isotretinoin and its main metabolite in the human, 4-oxo-isotretinoin, induce malformations similar to those seen in vivo. Since during normal repetitive dosing in the human the mean trough blood concentration of isotretinoin ranges from 132 to 196 ng/ml, while 4-oxo-isotretinoin ranges from 610 to 791 ng/ml, it is likely that the metabolite plays a major role in the induction of the isotretinoin embryopathy.

Predation on juvenile coral reef fishes : an exclusion experiment

Abstract: The densities of recruits on caged and uncaged areas were compared in an experiment done to show the extent of predation on recently metamorphosed coral reef fishes. The design was unlike typical caging experiments, however, in that areas were caged only for short periods of 20–30 days and several independent trials, testing the same null hypothesis, were run. This was done to avoid confounding the effects of excluding herbivorous fishes with the effects of excluding piscivorous fishes. A third treatment, partially-meshed cages, revealed that the experiment was complicated by several other factors. Some prey species were attracted to the high relief offered by the experimental structures. Others responded to the differences in shelter from predators by redispersing themselves among the treatments shortly after settlement. There was also at least one significant “edge” effect caused by fishes preferring to settle near the boundaries of all treatments. In spite of these difficulties, observations on known individuals revealed that rates of mortality were age-dependent and decreased rapidly after metamorphosis. More than 25% of such fishes disappeared during their first five days in the benthic habitat compared with >10% of fishes aged 6–10 days and no losses of fishes aged 11–15 days. These early losses are the greatest instantaneous rates of mortality yet documented for recruited reef fishes. The experiment also suggested different rates of early mortality for various groupings of species: individuals of solitary, sedentary species disappeared approximately half as fast as individuals of the more mobile, and the more gregarious, species. This is probably a true reflection of the different vulnerability of these groups to predation and it may be caused by the different ways in which these fishes use the coral substratum. Our experience suggests that caging artifacts can have major impacts on the results obtained from this type of experiment and they must be controlled for adequately. We conclude that studies of predation on reef fishes may be done more easily using other methods.

Human T-cell clones recognize a major M. leprae protein antigen expressed in E. coli

Abstract: Leprosy is a chronic infectious disease caused by Mycobacterium leprae. As with other intracellular parasites, protective immunity is dependent on T cells and cell-mediated immunity. In animal models, immunization with killed armadillo-derived M. leprae elicits strong T-cell responses, delayed-type hypersensitivity and protection against viable challenge. We have recently shown that killed M. leprae can induce delayed-type hypersensitivity in healthy human volunteers. Identification of the M. leprae antigens that are recognized by T cells and may be involved in protection has been hampered by the inability to cultivate the organism in vitro and by difficulties in antigen purification from limited quantities of armadillo-derived bacillus. Because genes for the major protein antigens of M. leprae as seen by mouse monoclonal antibodies have been isolated, it has become possible to test whether these individual antigens are recognized by T cells. We screened crude lambda gtll phage lysates of Escherichia coli containing individual M. leprae antigens using M. leprae-specific T-cell clones isolated from M. leprae-vaccinated volunteers. Using this method, we find that nearly half of the M. leprae-specific T-cell clones are stimulated to proliferate by lysates containing an epitope of a M. leprae protein of relative molecular mass 18,000 (18K).

Sexual differences in morphology and niche utilization in an aquatic snake, Acrochordus arafurae.

Abstract: Filesnakes (Acrochordus arafurae) are large (to 2 m), heavy-bodied snakes of tropical Australia. Sexual dimorphism is evident in adult body sizes, weight/length ratios, and body proportions (relative head and tail lengths). Dimorphism is present even in neonates. Two hypotheses for the evolution of such dimorphism are (1) sexual selection or (2) adaptation of the sexes to different ecological niches. The hypothesis of sexual selection is consistent with general trends of sexually dimorphic body sizes in snakes, and accurately predicts, for A. arafurae, that the larger sex (female) is the one in which reproductive success increases most strongly with increasing body size. However, the sexual dimorphism in relative head sizes is not explicable by sexual selection.The hypothesis of adaptation to sex-specific niches predicts differences in habitats and/or prey. I observed major differences between male and female A. arafurae in prey types, prey sizes and habitat utilization (shallow versus deep water). Hence, the sexual dimorphism in relative head sizes is attributed to ecological causes rather than sexual selection. Nonetheless, competition between the sexes need not be invoked as the selective advantage of this character divergence. It is more parsimonious to interpret these differences as independent adaptations of each sex to increase foraging success, given pre-existing sexually-selected differences in size, habitat or behavior. Data for three other aquatic snake species, from phylogenetically distant taxa, suggest that sexual dimorphism in food habits, foraging sites and feeding morphology, is widespread in snakes.

The influence of a shortage of hosts on the specificity of oviposition behaviour in species of Dacus (Diptera, Tephritidae)

Abstract: . When deprived of their preferred hosts for up to 16 days prior to behaviour assays, three relatively specialized tephritid flies, D. cacuminatus (Hering), D. cucumis French and D. jarvisi (Tryon), retain strong preferences for their particular hosts. Moreover, in the absence of the preferred hosts, D. cacuminatus, and to a lesser extent D. cucumis, will not accept fruits that are outside their normal host range. D. jarvisi readily accepts other fruits in the absence of its preferred host, Planchonia careya, but in common with the other two shows no increase in the number of eggs laid with increasing periods of deprivation. None of these species accumulate oocytes when deprived of fruits. In contrast, the highly polyphagous D. tryoni Frogg. lays more eggs and oviposits readily into a previously unacceptable fruit after 4 days without access to hosts. This change in behaviour is associated with a marked increase in the number of mature eggs carried by females. These results suggest an important difference between the generalist and more specialized species in the physiological control of oocyte maturation. In D. tryoni there appears to be no inhibition of oocyte development once the primary follicle has matured, whereas in the other species each ovariole contains no more than one mature egg. In D. tryoni, the change in behaviour which accompanies this increase in egg load, may influence its propensity to accept unusual fruits, and may help to explain its rapid acceptance of most cultivated fruits introduced to Australia.

An Intonational Change in Progress in Australian English.

Abstract: Many speakers of current Australian English often use a high-rising intonation in statements. This usage, which has been termed Australian Questioning Intonation (AQI), has a nonpropositional, interactive meaning (checking for listener comprehension) and interacts with the turn-taking mechanism of conversation. A quantitative study of the use of AQI in Sydney reveals that it has the social distribution characteristic of a language change in progress: higher rates of usage among working-class speakers, teenagers, and women. Real time data confirm this, showing that the form was almost nonexistent in this speech community two decades earlier. The social motivations of this innovation are examined in terms of local identity and the entry of new ethnic groups into the community, and possible linguistic sources are discussed. The utility of quantitative methods in studying meaningful linguistic variables is demonstrated. (Australian English, language change in progress, intonation, sociolinguistic variation, social class, social motivation)

Multidimensional Self-Concepts A Long-Term Follow-Up of the Effect of Participation in an Outward Bound Program

Abstract: Marsh, Richards, and Barnes (1986) examined systematic change and stability in multiple dimensions of self-concept and the effects of participation in a 26-day residential program called Outward Bound. Multidimensional self-concepts measured with the Self Description Questionnaire (SDQ) III increased as a consequence of the intervention and the increases were significantly larger for those facets judged a priori to be more relevant to program goals. For purposes f the present investigation participants from the previous study were asked to complete the SDQ III again, 18 months after completion of the program; and there was little systematic change in the multidimensional self-concepts during the long-term follow-up interval. Coupled with the results of the earlier study and further examination of the psychometric properties of the SDQ III, these findings further support the Outward Bound program as an effective intervention for enhancing self-concept and the construct validity of responses to the SDQ III....

The cardio-selectivity of himbacine: a muscarine receptor antagonist.

Abstract: The antimuscarinic actions of himbacine were compared with those of atropine and/or homatropine on atria, ileum and trachea from guinea-pigs and rat uterus preparations. 1. The antagonism of acetylcholine or carbachol by all the antagonists was competitive on the preparations studied. The pA2 values of himbacine in all smooth muscle preparations were similar )around 7.2) whereas in atria it exhibited about 10-fold higher affinity (pA2=8.2). 2. In contrast, both atropine and homatropine had similar affinities for muscarine receptors (pA2 values around 9.1 and 7.2 respectively) in both atria and smooth muscle. 3. It may be concluded from these results that cardiac and smooth muscle muscarine receptors are not homogeneous and that himbacine is a relatively potent and selective antagonist for cardiac receptors. 4. The cardio-selectivity of himbacine supports the concept of heterogeneity of muscarine receptors.

Privatization Policies and Public Enterprise: A Survey*

Abstract: This paper surveys and analyzes the economic literature on ‘privatization’ policies, restricting coverage to policies designed to improve the operating efficiency of public sector enterprises through increased exposure to competitive market forces These include asset sales, liberalization (or deregulation) and franchising The objectives, incentives and constraints of public and private enterprises are examined, and evidence on their comparative performance is analyzed Public sector revenue effects from asset sale are also explored On the basis of these considerations, the paper concludes that liberalization is an important ingredient in any policy package designed to improve the operating efficiency of public sector enterprises Asset sale may enhance the beneficial impact of deregulation but asset sale in the absence of deregulation is unlikely to improve efficiency, and may introduce additional market distortions Franchising is seen as an appropriate mechanism for privatization when the market is inherently monopolistic and when the government desires to retain control over output and/or price

Population dynamics of the shrub Acacia suaveolens (Sm.) Willd.: Fire and the transition to seedlings

Abstract: Fire, through soil heating effects, causes flushes of seed germination in Acacia suaveolens. Optimal temperatures for germination are between 60 and 80°C for any duration, or up to 100°C for durations less than 1 h. Exposure to temperatures less than 60°C leaves seeds dormant and viable, whilst seed death occurs in increasing proportions with increasing exposure to temperatures greater than 80°C. A field study of temperatures in the soil under simulated burns showed that the innate seed dormancy in A. suaveolens would only be broken for seeds up to a depth of 1 cm in ‘cool’ or 4 cm in ‘hot’ burns. In the hot burns some of the seeds in the top 1 cm of the soil were killed by excessive heating. These simulated burns most resemble cool and moderate/high intensity wildfires, respectively. Seeds can emerge from depths up to 8 cm and, for any seeds buried deeper than this, the probability of emergence is progressively reduced down to nil at 14 cm. Seeds buried between 5 and 10 cm will be heated sufficiently to break their dormancy only in a very high intensity wildfire. Seeds buried between 5 and 10 cm deep mostly occur in nests of an ant, Pheidole sp. Field observations of emergent seedlings confirm that post-fire emergence is concentrated over a small range of soil depths directly related to the intensity and duration of heating that occurs, whilst occasional seedlings may appear from greater or lesser depths largely dependent upon the spatial heterogeneity of soil heating in natural fires.

A streamline element scheme for solving viscoelastic flowproblems part II: Integral constitutive models

Abstract: A finite element method for using integral constitutive models in viscoelastic flow simulation is presented. This method is based on a streamline element scheme (S.E.S) which was reported in Part I of this paper. The technique of particle tracking and strain history calculation is discussed in detail. In calculating the infinite memory integral, either Gaussian or Laguerre numerical quadrature formulae are used in our scheme. Some simple and complex flow problems involving the upper-convected Maxwell integral model are solved as test problems and afterwards the effort is concentrated on the K.B.K.Z. model. Much numerical work is devoted to simulating the axial extrusion swell experiments with LDPE sample A of the IUPAC Working Party on Structure and Properties of Commercial Polymers, using a specific version of the K.B.K.Z. model with multiple relaxation times in the memory function designed by Papanastasiou, Scriven and Macosko. It is shown by the numerical results that if the shear viscosity function of the model is kept unchanged, the calculated swelling ratio is very sensitive to the elongational behaviour of the model; it increases (or decreases) monotonically with the increase (or decrease) of the elongational viscosity in the corresponding stretching rate region. When both the shear and elongational response of this model agree well with experiments, the numerical predictions of the swelling ratio also agree well with experimental data at low and high apparent shear rates, while in the medium region the numerical calculation underestimates the swelling ratio. It is also seen that, using this model in our method, the extrusion calculation is surprisingly stable, even at very high Weissenberg numbers or very high extrusion swelling ratios, thus showing the very promising potential of integral models in the field of viscoelastic flow computation.

Removal of singularities in tresca and mohr–coulomb yield functions

Abstract: The Tresca and Mohr–Coulomb yield functions are used widely in metal and soil plasticity computations. Both of these criteria, however, possess angular vertices at which the gradient with respect to the stresses, and hence the elastoplastic constitutive law, is undefined. This paper describes a modified yield function which may be used to ‘round-off’ these vertices. When used in conjunction with the parent yield function, the modified yield function results in a yield surface which is continuous and differentiable for all values of the stresses. The modified yield function is used in the vicinity of the vertices and is given in a form suitable for finite element programming.

Light-induced giant dipoles in simple model compounds for photosynthesis

Abstract: The primary steps in photosynthesis involve very rapid (sub-nanosecond) electron transfer between molecular entities that are rigidly embedded within a lipid membrane and separated from each other by well-defined distances on the order of 10 A. In an attempt to simulate such systems we have studied photon-induced electron transfer within specially synthesized molecular assemblies in which a donor moiety is separated from an electron acceptor by a rigid, saturated hydrocarbon framework of variable length, from 5 to 13 A. We find charge separation to occur on a sub-nanosecond timescale with close to unit quantum efficiency in all cases. The lifetimes of the resulting charge-transfer states, with dipole moments approaching 70 debye units, can extend to several hundred nanoseconds. Non-conjugated hydrocarbon bridges may be important in determining the rate and direction of electron transfer in photo-excited natural or artificial molecular systems.