Showing papers by "University of Sydney published in 1984"

Self Description Questionnaire III: The construct validity of multidimensional self-concept ratings by late adolescents.

Abstract: This research examines the validity of self-concept interpretations of scores from a new instrument for use with university-aged respondents. The Self Description Questionnaire III (SDQ III) was designed to measure 13 factors of self-concept, and these dimensions were identified with conventional and confirmatory factor analyses. In two different studies, the reliabilities of the 13 factors were high (median alpha = 0.89) and correlations among the factors were low (median r = 0.09). Correlations among a wide variety of validity criteria and the multiple dimensions of self-concept measured by the SDQ III formed a logical and theoretically consistent pattern of relationships. Academic achievement measures in language and mathematics were substantially correlated with self-concepts in the same areas but not with other self-concept factors. Ratings by significant others for all 13 SDQ HI scales were substantially correlated with the measures of corresponding self-concepts, but were not substantially correlated with the measures of noncorresponding self-concepts. These findings offer strong support for the construct validity of both self-concept and interpretations based upon the SDQ III.

Psychological Constraints on the Teachability of Languages

Abstract: This paper reports on the influence of formal instruction on L2 acquisition in an instructional experiment with child learners. The main tendency of the findings is that a structure can only be learned under instruction if the learner's interlanguage has already reached a stage one step prior to the acquisition of the structure to be taught.My hypothesis for an explanation suggests that the teachability of L2 structures is constrained by the same processing restrictions that determine the developmental sequences of natural L2 acquisition: since the processing procedures of each stage build upon the procedures of the preceding stage there is no way to leave out a stage of the developmental sequence by the means of formal teaching. Following such a processing capacity approach I reject the assumption that the constraints on teachability can be explained on the basis of linguistic input.

Numerical study of the Bingham squeeze film problem

Abstract: In studies of the flow of a Bingham fluid in a parallel-plate plastometer there has been disagreement about whether or not a yield surface exists, and if it does exist what shape the yield surface has. The present authors have re-exemined the problem using a finite element program and have concluded that a small plug of unyielded fluid exists adjacent to the centre of the plates. This result has been verified by replacing the unyielded plug with a solid body.

Shakedown of pavements under moving surface loads

Abstract: Procedures for the analysis of the shakedown of pavements are developed. The approach employed models the elastoplastic behavior of a horizontally‐layered continuum subjected to repeated moving loads, and permits the incremental process of pavement failure to be considered. Following an examination of the effect of materials and geometry upon the shakedown of a half‐space and a two‐layer continuum, the analysis is applied to the results of a comprehensive road test. It is found that pavement shakedown may be both observed and satisfactorily predicted, and further that the life under traffic of weaker pavements may be conveniently estimated. An outline of a possible design approach utilizing the theory concludes the paper.

Endocrine Response in the Fallopian Tube

Abstract: I. INTRODUCTION: STRATIFICATION OF TUBAL ENDOCRINE RESPONSE THE FALLOPIAN TUBE has, until very recently, been essential for human reproduction. Sperm transport and capacitation, ovum transport, fertilization, and early embryogenesis are fundamental reproductive events that normally take place in its lumen. Although in recent times in vitro fertilization (IVF) procedures have sought to mimic the tube's luminal environment, the still limited success of IVF carries the certain implication that more detailed knowledge of fallopian tube function may not only improve treatment of its anatomical and physiological disturbances but also should provide a better empirical basis for its in vitro counterpart. Fallopian tube physiology is exquisitely dependent on hormones. The responsive tissues include the muscle layer (or myosalpinx), the vasculature, the epithelium (or endosalpinx) and, most important, the fluids contained in the lumen. Intricate tiers of endocrine influences and responses in the human fallopian tub...

Osteogenesis imperfecta type III. Delineation of the phenotype with reference to genetic heterogeneity

Abstract: A group of fetuses with a perinatally lethal variety of osteogenesis imperfecta (O.I. type II) is charaterized by short limbs, and clinical and roentgenological evidence of severe osseous fragility and defective ossification. Forty-eight cases were reviewed and can be subdivided into 3 groups on the basis of small but probably significant differences in clinical and radiographic findings. Group A (38 cases): short, broad, “crumpled” long bones, angulation of tibiae and continuously beaded ribs. Group B (6 cases): short, broad, crumpled femora, angulation of tibiae but normal ribs or ribs with incomplete beading. Group C (4 cases): long, thin, inadequately modelled, rectangular long bones with multiple fractures and thin beaded ribs. Consistency of findings within sibships suggests the groups reflect genetic heterogeneity. An increased frequency of parental consanguinity, sib occurrence with normal parents, and normal mean paternal age at birth, suggest that most cases of O.I. type II represent autosomal recessive traits. Some previously reported cases and the biochemical findings in one case suggest still further genetic heterogeneity.

Who do Diffusion flames Emit smoke

Abstract: The causes of smoke emission from free gaseous laminar diffusion flanles are investi-gated. Soot concentration, temperature and velocity profiles were measured around the smokepoint for a range of fuels. Smoke was emitted when the temperature in the burnout region droppedbelow about 1300 K.A smoking flame stopped emitting smoke when the temperature in the burnout region wasslightly raised locally by absorption of energy from a COz laser beam.The temperature drop in the flame is strongly coupled to soot concentration through radiationlosses. Soot formation rates are in turn influenced by heat losses and residence times near thefuel nozzle tip. Thus conditions near the nozzle influence the smoke point. The results are alsodiscussed in context with turbulent diffusion flame smoke emission.

Self-Concept: The Application of a Frame of Reference Model to Explain Paradoxical Results.

Abstract: Academic abilities were substantially correlated with academic self-concept for Year 6 students (n = 305), but were uncorrelated with non-academic self-concepts. Schools for this study were specifi...

Vertical and seasonal patterns in competition for microalgae between intertidal gastropods.

Abstract: Grazing by the snail Nerita atramentosa and the limpet Cellana tramoserica caused similarly great reductions in abundance of microalgae — measured by direct counts and by estimation of chlorophyll analyses. A smaller snail, Bembicium nanum, caused smaller reductions of microalgal resources, compared with ungrazed areas. These results were consistent with the competitive abilities of these three species. Chlorophyll concentrations in samples of grazed rocks were reliable estimates of the nature and abundance of food available to the grazers.

Electron‐cyclotron maser emission: Relative growth and damping rates for different modes and harmonics

Abstract: The temporal growth rate and the number of e-folding growths are calculated and compared for the following wave modes due to a loss-cone-driven cyclotron maser: fundamental x, o, and z modes and second harmonic x and o modes. The dominant mode of the maser should be the fastest growing mode for a saturated maser and should be the mode with the greatest number of e-folding growths for an unsaturated maser; this mode is the fundamental x mode) for a plasma frequency to cyclotron frequency ratio of less than about 0.3; it is the z mode (or perhaps the fundamental o mode) for ratios between 0.3 and 1.0, and the z mode (or perhaps the second harmonic x mode) for ratios between 1.0 and 1.3. Two main points are made: the dominance of the z mode over the range of ratios considered and the very weak effect of cyclotron damping. Electron-cyclotron maser emission is seen as responsible for auroral kilometric radiation, decametric radio emission from Jupiter and Saturn, solar microwave spike bursts, and microwave emission from some flare stars.

Testicular function in potential sperm donors: normal ranges and the effects of smoking and varicocele.

Abstract: Testicular exocrine (semen analysis) and endocrine (plasma LH, FSH, prolactin and testosterone) function was assessed in 119 consecutive healthy men presenting for screening as potential sperm donors Since these volunteers were unbiased with respect to their fertility status, this sample of the general male population was suitable to determine normal ranges and the influence of a variety of physical (height, weight, standardized body weight, varicocele) and demographic (age, marital and fertility status, tobacco and alcohol consumption) factors on normal human testicular endocrine and exocrine function, without the confounding effects of bias in selection of subjects The statistical distribution of all seminal parameters was non-gaussian, but cube-root transformation of the data normalized the distribution, allowing for parametric statistical analysis The median (and 95% confidence limits) for the various semen parameters was 730 (106-2353) million sperm per ml; 1890 (126-868) million sperm per ejaculate; 504 (59-1819) million motile sperm per ml; 1330 (69-6617) million motile sperm per ejaculate; 540 (70-1729) million morphologically normal sperm per ml and 1385 (75-672) million morphologically normal sperm per ejaculate Testicular volume was correlated positively with measures of physique such as standardized body weight (r = 025, P less than 001) and body surface area (r = 030, P less than 0002), and negatively with plasma levels of FSH (r = -031), P less than 0002) but not LH Sperm output was positively correlated with testicular volume (r = 028, P less than 0005) and negatively correlated with plasma FSH (r = -031, P less than 0002) and plasma LH (r = -031, P less than 0002) Smoking was associated with a highly significant reduction in sperm output and motility Men with varicocele (25%) were significantly taller, had slightly lower haemoglobin levels and moderate left (but not right) testicular atrophy, but neither seminal nor hormonal parameters were different from men without varicocele There was no difference in any markers of human testicular function between men according to marital or fertility status, grades of moderate alcohol consumption or the presence of low titres of sperm antibodies

Choice of microhabitats by coral reef fishes at settlement

Abstract: A set of small lagoonal patch reefs was searched every 1 to 3 days during the peak recruitment seasons of three summers and newly settled juvenile fishes were located. The majority of species remain rather sedentary during the first few days in the demersal environment, and we assumed that the site occupied was the site chosen at settlement. A series of characteristics of the occupied site were recorded, including percent cover of different types of substratum, and attributes related to the site's position on the patch reef. A set of null sites was randomly located on the same reefs for comparison with those selected by the fish. Sites chosen by individuals of eight common species were compared with these null sites, and sites chosen by fourteen species (including the eight) were compared with each other. Multiple discriminant analysis was used to assess the degree to which each species selected a unique type of site, and, for the eight species, the degree to which sites chosen by fish could be discriminated from randomly selected sites on the same patch reefs. Chosen sites were readily discriminated from null sites in seven of eight species, however the procedure was poor at discriminating among sites chosen by different species, and 8 pairs of species among the 14 chose sites which on average did not differ in the attributes measured. Attributes most important in discriminating sites chosen by each species are considered. Overall, the results indicate that while juvenile fish do not settle indiscriminantly onto lagoonal patch reefs, sites chosen by different species are often not very different from one another.

Large scale spatial and temporal variation in recruitment to fish populations on coral reefs.

Abstract: Visual census was used to sample young of the year of fish species recruited to each of two habitats on seven lagoonal platform reefs of the Capricorn-Bunker Group, Great Barrier Reef. The reefs sampled span an area 70 km in extent. In 1983, 62 species from 13 families were detected as recruits on reef slope sites. The total number of cruits, and the number of each of 6 of 16 species tested, differed significantly among reefs, despite the fact that differences among sites within reefs did not exist, and that sampled slopes were chosen to be hydrographically, and physiographically as similar as possible. Lagoonal patch reefs were sampled in two years. In 1982, 76 species of 11 families occurred as recruits. In 1983, 86 species of 12 families were recorded. All of 22 species common enough to test showed some significant variation in abundance among reefs, years, or both. For 9 species, significant year x reef interactions occurred, demonstrating that relative recruitment success among reefs varied between years. Reasons for the substantial levels of variability are discussed, and implications for the organisation of reef fish communities are considered.

Kinetics of emulsion polymerization of methyl methacrylate

Abstract: The kinetics of the emulsion polymerization of methyl methacrylate at 50 degree C have been studied in seeded systems using both chemical initiation and gamma -radiolysis initiation. The data are quantitatively interpreted using a generalized Smith-Ewart-Harkins model, allowing for free radical entry, exit, bimolecular termination within the latex particles, and aqueous phase hetero-termination and re-entry. From this treatment, there results (i) the dependence of the termination rate coefficient (k//t) on the weight fraction of polymer (w//p), (ii) lower bounds for the dependence of the entry rate coefficient on initiator concentration, and (iii) the conclusion that most exited free radicals undergo subsequent reentry into particles rather than hetero-termination. The results for k//t(w//p) are consistent with diffusion control at temperatures below the glass transition point. Comparisons are presented of the behavior of methyl methacrylate, butyl methacrylate, and styrene in emulsion polymerization systems.

The influence of environmental temperature, age and sex on the digestibility of amino acids in growing broiler chickens

Abstract: 1. The ability of the broiler chicken to metabolise energy and to digest and absorb amino acids increased from 30 to 50 d of age. 2. Although sex had no major effect on metabolisable energy or amino acid digestibilities at these ages, the influence of environmental temperature on amino acid digestibilities appeared to be sex‐related, there being decreased digestibilities of most amino acids at higher temperatures in female but not male birds.

Deeper than Deep Ecology: The Eco-Feminist Connection

Abstract: This chapter offers a feminist critique of deep ecology as presented in the seminal papers of Ame Naess and Bill Devall. It outlines the fundamental premises involved and analyzes their internal coherence. Not only are there problems on logical grounds, but the tacit methodological approaches of the two papers are inconsistent with the deep ecologists’ own substantive comments. It discusses these shortcomings in terms of a broader feminist critique of patriarchal culture and points out some practical and theoretical contributions which eco-feminism can make to genuinely deep ecology problematic.

Bacillus subtilis as a control agent against fungal pathogens of citrus fruit

Abstract: Several fungal and bacterial antagonists of the citrus fruit pathogens, Alternaria citri and Geotrichum candidum , were isolated from fruit that had survived incubation under conditions conducive for decay. In vitro, Bacillus subtilis was the most active antagonist and was also active against Penicillium digitatum . Dipping wounded fruit in suspensions of bacterial cells markedly controlled decay by each of A. citri, G. candidum and P. digitatum . Culture filtrates of B. subtilis were also shown to be antagonistic to A. citri and G. candidum in vitro and in vivo . Spores of B. subtilis were readily produced, stored as powders and then reconstituted to act as potential control agents.

The essential work of fracture for tearing of ductile metals

Abstract: A simple energy balance analysis is presented for the tearing of ductile sheet metals using the trousers test. It is shown that the specific essential work of fracture (w e ) for tearing can be estimated by extrapolating the straight line relationship between the tearing force per unit thickness and the trousers leg width to zero leg width. There are two contributions to the specific essential work of fracture: one is due to the localised plastic shearing work in a zone contiguous with the torn edges (w e1 ) and the other is the final out-of-plane tearing work (w e2 ).

A numerical simulation of a plastic fluid in a parallel-plate plastometer

Abstract: The parallel-plate plastometer provides a simple experimental method for determining the rheological properties of plastic fluids. Previous theoretical analyses of flow in the plastometer have lead to conflicting results. In this paper, a numerical method is used to solve the plastometer flow problem and resolve some questions regarding the theoretical analysis. The plastometer problem is also used to demonstrate the accuracy of the numerical method in obtaining solution to non-trivial problems involving fluids with a yield stress.

Nutrition and Sports Performance

Abstract: During the past 20 years there have been great developments in the scientific understanding of the role of nutrition in health and physical performance. Epidemiological and physiological studies have provided evidence that certain forms of dietary behaviour may be linked with an increased risk of developing disorders such as high blood pressure, coronary artery disease and some cancers. This has resulted in dietary recommendations that are intended to reduce the incidence of these disorders in the community. The science of nutrition in relation to sports performance has progressed from empirical studies investigating the effects of dietary manipulations, such as restriction and supplementation, to the direct investigation of the physiological basis of the specific nutritional demands of hard physical exercise. This review is based on the premise that it is ‘what comes out’ rather than ‘what goes in’, which provides the clues to ideal nutrition for athletic performance. Various aspects of the physical demands of athletic exercise are viewed as stresses that induce specific biochemical, and hence nutritional, strains in the athlete. Training is the predominant demand in the athletic lifestyle. This is characterised by acute bouts of high power output. During one hour of hard training an athlete may expend 30% of his or her total 24-hour energy output. These high power outputs have important implications for energy substrate and water requirements. Carbohydrate, specifically muscle glycogen, is an obligatory fuel for the high power outputs demanded by athletic sports. Muscle glycogen is a limiting factor in hard exercise because it is held in limited amounts, utilised rapidly by intense exercise, and fatigue occurs when it is depleted to low levels in the active muscles. Liver glycogen may also be exhausted by hard exercise and low blood glucose contributes to fatigue. High sweat rates are demanded during severe exercise and large water deficits commensurate with energy expenditure are incurred during extended periods of hard training and competition. Salt, potassium, and magnesium are lost in nutritionally significant amounts in the sweat, but vitamins and trace elements are not. Adaptive mechanisms protect athletes against electrolyte depletion. Iron loss in sweat may contribute to the iron deficiency seen in some endurance runners. Protein is degraded and amino acids are oxidised during physical exercise. Protein is also retained during muscle building training. Recent investigations indicate that the minimal protein requirements of athletes may be substantially higher than those for sedentary persons. Nonetheless, all the protein that athletes need will be supplied by a conventional diet and protein supplements are not required. There is no evidence that athletes have extraordinary vitamin requirements. Some endurance runners, adolescent and female athletes are at risk of iron depletion with or without obvious anaemia. These people require nutritional counselling and may benefit from supervised iron supplementation. The major nutritional demands arising from hard athletic exercise are for carbohydrate and water. Liberal carbohydrate and water consumption is essential for full recovery between training sessions and in preparation for competition. The pre-competition meal provides limited benefits other than promoting full hydration. Large intakes of simple carbohydrates close to competition may precipitate hypoglycaemia and impair performance. During exercise, water consumption to replace sweat losses is the major concern. The formulation of nutritional guidelines for athletes, based on the physiological demands of athletic exercise, indicates that the ideal dietary pattern for athletes coincides in most repects with internationally recognised recommendations for a healthy diet. A review of the limited published information on dietary habits of athletes indicates that, in general, they do not select diets that promote either good health or optimal performance.