Showing papers by "University of New South Wales published in 1988"

Problems of rainfall-runoff modelling in arid and semiarid regions

Abstract: The distinctive features of arid and semiarid regions affect rainfall-runoff modelling on both a discrete event basis and a continuous basis. The general characteristics of arid zone hydrological processes and the problems that they present in runoff modelling are discussed. Both sloping lands with integrated stream networks and flatlands with repetitive micro-hydrology are considered. The wide diversity in some characteristics may require different parameter values and possibly different approaches in different regions. Lack of observed data provides the major problem for runoff modelling in arid regions. Some comments are given on appropriate approaches to modelling for sloping regions.

Electro-acoustic effects in a dilute suspension of spherical particles

Abstract: Sound waves can be generated in a colloid by the application of an alternating electric field. In this paper we describe the method for calculating this and the related electro-acoustic phenomenon of electric fields generated by sound waves. As an illustration of the procedure, we obtain formulae for these two effects for a suspension of spherical particles with thin double layers, in a parallel plate geometry.

Modeling multiattribute utility, risk, and belief dynamics for new consumer durable brand choice

Abstract: This paper proposes a brand choice model to aid in the prelaunch management of a new consumer durable entry in an existing category. The model contributes to theory by integrating the critical phenomena of multiattribute preference, risk, and dynamics in an individual level expected utility framework. The integration is based on established theoretical constructs in utility, Bayesian decision analysis, and discrete choice theory. Measurement and estimation procedures are presented, an application is described, and the managerial relevance of this work as a planning and forecasting tool is examined.

Isolation of a spiral-shaped bacterium from the cat stomach.

Abstract: A spiral- or helix-shaped bacterium that colonizes the stomachs of cats has been isolated in pure culture for the first time. The organism is tightly coiled with tufts of 10 to 17 polar flagella positioned slightly off center at the end of the cell. The body of the cell is entwined with unique periplasmic fibrils that usually occur in pairs, although groupings of one and three fibrils were also seen. The organism is strongly urease, catalase, and oxidase positive and is likely to belong to an as yet unclassified group of bacteria that are specifically adapted to the ecological niche provided by gastrointestinal mucus. Isolation of this organism will allow study of the factors influencing colonization of gastric mucosae, information relevant to the association of another mucus colonizer, Campylobacter pylori, with the human stomach. Recent reports of the isolation of other bacteria with the characteristic periplasmic surface structures suggests that the group may be more widespread than was hitherto thought. Bacteria with the morphology of the organisms seen in the cat stomach have been seen in gastric biopsies from humans. The organism whose isolation is reported here has been used in previous serological studies to support the hypothesis that spiral bacteria from animals can colonize the human stomach.

Transformational and Coercive Strategies for Planned Organizational Change: Beyond the O.D. Model

Abstract: This paper challenges the universality of O.D. theory, arguing that it presents an incomplete model of organizational change. Two contrasting 'theories' of organization al change are compared and evaluated (the incremental and transformational theses) and also two contrasting methods of change: participation and coercion. All four approaches are seen as legitimate components of a differentiated contingency model of change. The model has implications for the choice of strategies for managing organizational change in differing circumstances and for the training of change agents.

Modes of spontaneous chromosomal mutation and karyotype evolution in ants with reference to the minimum interaction hypothesis.

Abstract: Aspects of chromosomal mutation and karyotype evolution in ants are discussed with reference to recently accumulated karyological data, and to detailed karyotype analyses of several species or species complexes with low chromosome number and unusual chromosomal mutations (the complexes of Myrmecia pilosula (Smith) (n=1, 5 or 9 to 16); M. piliventris Smith (n=2, 3-4, 17 or 32), and Ponera scabra Wheeler (n=3 or 4, 2n=7 or 8)). Translocations and Robertsonian polymorphisms are confirmed to be non-randomly distributed among ants -the former are found at high frequencies in species with low chromosome numbers (n≤12), while the latter predominate in those with high numbers (n>12). This situation is consistent with the minimum interaction hypothesis of Imai et al. (1986), under which translocations are expected to occur most frequently in low-numbered karyotypes, and that the resulting genetic risks are minimized by increases in chromosome and/or arm numbers through centric fission and pericentric inversion. Centric fusion is considered to be a transient event in karyotype evolution, resulting from telomere instability in acrocentric chromosomes.

The Long-Term Outcome of Depressive Illness

Abstract: One hundred and forty-five patients with primary depressive illness admitted to a university hospital between 1966 and 1970 were followed up an average of 15 years later. Adequate data were obtained on 133 (92%) of the 145. During the follow-up period, 7% of the 133 had suicided, 12% had remained incapacitated by illness and only 20% had remained continuously well. Patients for whom the index admission was not their first were especially likely to be readmitted during the follow-up period. Patients with endogenous depression, none of whom developed schizophrenia during the follow-up period, were more likely to need readmission than patients with an index diagnosis of neurotic depression. In all other respects the prognosis for the two types of depression was the same, with considerable morbidity evident in both.

H/sub infinity /-optimal control with state-feedback

Abstract: A H/sub infinity /-optimal control problem in which the measured outputs are the states of the plant is considered. The main result shows that the infimum of the norm of the closed-loop transfer function using linear static state-feedback equals the infimum of the norm of the closed-loop transfer function over all stabilizing dynamic (even, nonlinear time-varying) state-feedback controllers. >

The development of a measure of intimate bonds.

Abstract: This paper discusses the relevance of assessing the nature of intimate relationships and reports on the development of such an instrument. The Intimate Bond Measure (IBM) is a self-report measure assessing two key underlying dimensions, care and control. Its properties are assessed in separate studies, establishing its high test-retest reliability, the homogeneous nature of the isolated dimensions, its insensitivity to broad socio-demographic influences and its minimal sensitivity to depressed mood state. Support for its validity, in terms of both perceived and actual characteristics of care and control, is demonstrated. It provides a simple and efficient measure of central constructs underlying intimate relationships, and is of potential use in studies attempting to assess the relevance of intimate relationships to the onset and course of psychiatric disorders.

Folic acid lowers elevated plasma homocysteine in chronic renal insufficiency: possible implications for prevention of vascular disease.

Abstract: To explore interrelations between folic acid and methionine metabolism in chronic renal insufficiency, we measured plasma amino acids in 21 patients with mean serum creatinine +/- SD of 560 +/- 240 mumol/L, after a ten-hour overnight fast, before and after administration of 5 mg of oral folic acid daily for 15 +/- 6 days. Mean plasma homocysteine was 12.9 +/- 6.8 mumol/L in the patients and 4.2 +/- 0.8 mumol/L in 24 normal controls (P less than .001), and after folic acid administration it declined in the patients to 6.8 +/- 2.8 mumol/L (P less than .0001) in linear proportion (r = .92) to the prefolate homocysteine level. Methionine concentrations were normal in the patients and did not change after folate administration, nor did elevated cysteine and creatinine. Plasma serine was lower (88.3 +/- 17.2 v 121 +/- 25 mumol/L, P less than .41) and declined further to 67.8 +/- 16.4 (P less than .0001) after folate, while prefolate glycine levels increased from 273.3 +/- 61.2 to 313.2 +/- 97.5 mumol/L (P less than .01). Serum and red-cell folate levels were normal in the patients before treatment. The results show that homocysteine levels are increased in chronic renal insufficiency, but may be lowered by folate enhancement of remethylation of homocysteine to methionine. Since elevated plasma homocysteine is associated with premature vascular disease, folic acid may reduce cardiovascular risk in chronic renal insufficiency.

Modeling Asymmetric Competition

Abstract: The effects of the marketing actions of one brand can be distributed among its competitors' market shares in a complex manner. This paper presents and illustrates methods for modeling brand competition and brand strategies in markets where competitive effects can be differentially and asymmetrically distributed. We discuss the empirical specification, parameter estimation and competitive---strategy implications of the models proposed. Price and advertising competition among eleven brands of an Australian household product is used to illustrate the application of these procedures.

Activation of human muscles at short muscle lengths during maximal static efforts.

Abstract: 1. Human muscle endurance is apparently enhanced during maximal voluntary contractions at short muscle lengths (McKenzie & Gandevia, 1987) but the ability of subjects to activate muscles fully at short lengths has not been established. Therefore this study examined the voluntary capacity to activate muscles fully at control (near resting) lengths and at decreased muscle lengths. Changes in mechanical properties of twitch responses to electrical stimulation of relaxed muscles at short muscle lengths were also documented. The abductor digiti minimi, elbow flexors and tibialis anterior were studied in five subjects. 2. For the three muscle groups, the mean reduction in twitch force between the control and short muscle lengths ranged from 46-51%. AT the short length there was a 9-13% reduction in the contraction time and a 21-27% reduction in the half-relaxation time. Maximal voluntary force declined by 21-49% at the short muscle length. A reduction in muscle length produced a shift to the right of the force-frequency curve as determined by brief trains of electrical stimuli. 3. During maximal efforts single or brief trains of two to four supramaximal stimuli, delivered to the parent nerve or motor point, failed to increase the force at a latency appropriate for onset of a muscle twitch in some but not all attempts. Each subject achieved 'maximal activation' of the muscle in a similar proportion of attempts at the control and short muscle lengths. 4. These results suggest that maximal voluntary activation of motoneurone pools is possible at short muscle lengths and that the central nervous system is able to maintain the discharge of motoneurones close to 'fusion' frequency despite a decrease in the temporal characteristics of the isometric twitch.

Early development of serotonin-containing neurons and pathways as seen in wholemount preparations of the fetal rat brain.

Abstract: The early development of serotonin-containing neurons was studied in wholemounts of the fetal rat brain (E12-E18). The wholemounts were treated immunocytochemically according to an immunoperoxidase technique to reveal a panorama of developing serotoninergic neurons. Serotoninergic neurons were localized to two discrete groups or clusters within the brainstem. Serotonin-containing neurons were identified first at E12 forming a rostral cluster of cells just caudal to the mesencephalic flexure. The more caudal cluster of cells first appeared at E14 in the medulla. During the period from E12 to E18, the immunoreactive cells increased in number and acquired a more complex dendritic tree while migrating to their permanent position. At E16, cells of the rostral group exhibited remarkably uniform mediolateral orientation. The rostral group of immunoreactive neurons gave rise to almost all ascending fibers, whereas the caudal group gave rise to the majority of descending fibers. Growing serotoninergic fibers were tipped by prominent growth cones, which were strongly immunoreactive. The fibers demonstrated prominent orientational selectivity with an almost total separation into ascending and descending bundles. Some of the ascending immunoreactive fibers displayed acute changes in their direction of growth, suggesting that the orientation of serotininergic fibers is mediated by directional cues that are specific to particular populations of serotoninergic fibers. Serotoninergic axons within the medial forebrain bundle were demonstrated particularly well and their ascent and rate of growth toward the forebrain could be easily followed. Immunoreactive fibers entered the telencephalon at E17 two portals, one along the lateral border of the hypothalamus and one rostrally, adjacent to the olfactory tubercle. In wholemounts at E18, fibers arising from this latter location could be followed as two distinct bands within the pallium; a basal band located ventrolaterally, adjacent to the lateral olfactory tract, and a dorsal band located at the medial edge of the telencephalon. Both fascicles were directed toward the occipital pole and contained unbranched fibers. At E18, serotoninergic axons arising from these two loosely organized fascicles covered most of the frontal telencephalon. The results of the present study indicate that wholemounts of embryonic brain can provide novel spaciotemporal data on the development of neuro-transmitter systems and may in the future prove to be useful experimental preparations in developmental neurobiology.

The effects of temperature and pH on the growth of yeast species during the fermentation of grape juice

Abstract: The effects of temperature and pH on the survival and growth of Saccharomyces cerevisiae, Kloeckera apiculata, Candida stellata, Candida krusei, Candida pulcherrima and Hansenula anomala were examined during mixed culture in grape juice. At 25°C, pH 3.0 and pH 3.5, S. cerevisiae dominated the fermentation and the other species died off before fermentation was completed. Saccharomyces cerevisiae also dominated the fermentation at 20°C but there was increased growth and survival of the other species. At 10°C the fermentation was dominated by the growth of both S. cerevisiae and K. apiculata and there was extended growth and survival of C. stellata and C. krusei. Juices fermented at 10°C exhibited ethanol concentrations between 7.4 and 13.4% and populations of K. apiculata, C. stellata and C. krusei in the range 106-108 cells/ml. However, these species produced maximum ethanol concentrations in the range 2.7–6.6% when grown as single cultures in grape juice.

Computational Fluid Dynamics: An Introduction

Abstract: This chapter provides an overview of computational fluid dynamics (CFD) with emphasis on its cost-effectiveness in design Some representative applications are described to indicate what CFD is capable of The typical structure of the equations governing fluid dynamics is highlighted and the way in which these equations are converted into computer-executable algorithms is illustrated Finally attention is drawn to some of the important sources of further information

Isolation and characterization of the bovine k-casein gene

Abstract: 1. The bovine kappa-casein gene has been isolated as a series of overlapping lambda clones and shown to consist of five exons distributed over a total length of approximately 13 kb. Most of the mature protein-coding sequence is contained in a single large exon. 2. Approximately 65% of the gene has been sequenced together with portions of the 5'- and 3'-flanking sequences. The immediate 5'-flanking sequence contains several motifs which are characteristic of upstream regions including a TATA box, a CAAT box, a sequence similar to that recognized by transcription factor AP-1 and a purine-rich sequence resembling that found upstream in all other lactoprotein genes. Other possible regulatory sequences are found upstream of exon 4. 3. The organization of the kappa-casein gene, together with its upstream sequence, confirms previous conclusions that it is unrelated to the calcium-sensitive-casein gene family to which it is linked. Evidence is presented which supports a previous suggestion that kappa-casein and the fibrinogens are evolutionarily related. 4. Intron sequences contain several examples of the A family of the artiodactyl Alu-like repeated sequences, together with a single example of a C-family sequence. The remainders of the introns of the kappa-casein gene, compared with the repeat elements and exons, are A + T-rich. 5. Among the lambda clones isolated, representatives were found of the A and B genetic variants which can be distinguished by restriction-enzyme analysis. Several other examples of polymorphisms in the non-coding region were found.

Modular function spaces

Abstract: This chapter introduces the general notions related to modular function spaces. The results discussed in this chapter is used throughout the rest of the book. This chapter also presents the reader with an exhaustive list of examples that will frequently reoccur in later parts of the book.

Cryptography: An Introduction to Computer Security

Abstract: Want to get experience? Want to get any ideas to create new things in your life? Read cryptography an introduction to computer security now! By reading this book as soon as possible, you can renew the situation to get the inspirations. Yeah, this way will lead you to always think more and more. In this case, this book will be always right for you. When you can observe more about the book, you will know why you need this.

Internal models and intermittency: A theoretical account of human tracking behavior

Abstract: This paper concerns the use of tracking studies to test a theoretical account of the information processing performed by the human CNS during control of movement. The theory provides a bridge between studies of reaction time and continuous tracking. It is proposed that the human CNS includes neuronal circuitry to compute inverse internal models of the multiple input, multiple output, dynamic, nonlinear relationships between outgoing motor commands and their resulting perceptual consequences. The inverse internal models are employed during movement execution to transform preplanned trajectories of desired perceptual consequences into appropriate outgoing motor commands to achieve them. A finite interval of time is required by the CNS to preplan the desired perceptual consequences of a movement and it does not commence planning a new movement until planning of the old one has been completed. This behavior introduces intermittency into the planning of movements. In this paper we show that the gain and phase frequency response characteristics of the human operator in a visual pursuit tracking task can be derived theoretically from these assumptions. By incorporating the effects of internal model inaccuracy and of speed-accuracy trade-off in performance, it is shown that various aspects of experimentally measured tracking behavior can be accounted for.

Field‐Based Education: Some Theoretical Considerations

Abstract: Within a broad notion of “the field”, teachers using field‐based methods work towards many different educational aims, some implicit and others explicit. Particular aims are examined, and some types of field activity are seen to be better for achieving certain aims than others. Types of field excursion are classified and some special learning benefits of working in the field are suggested. Field teachers should set clear learning objectives and carefully plan and select the experiences they intend students to have, taking into account educational aims, time available, distance, student readiness, and availability of localities and resources. Thorough briefing and debriefing are important in maximising field learning.

Reduction in perceived intensity of cutaneous stimuli during movement: a quantitative study.

Abstract: The effect of movement of the index finger on the perceived intensity of trains of electrical stimuli to the digital nerves of the same finger was studied quantitatively using a novel intramodality stimulus-matching task Subjects consistently were able to match reliably the perceived intensity of stimuli delivered on the 'reference' side with that of stimuli delivered simultaneously to the digital nerves of the index finger on the other ('matching') side Both active and passive movement of the index finger (on the reference side) in the palmar plane reduced the matched stimulus voltage by about 10% of its control value for stimuli at twice the sensory threshold This reduction in perceived intensity did not persist beyond the period of stimulation An isometric contraction of first dorsal interosseous muscle produced a smaller, but statistically significant, reduction in perceived intensity Non-noxious electrical stimulation of the digital nerves of the ipsilateral thumb or little finger also reduced the perceived intensity of stimuli to the index finger Perceived intensity of stimuli during movement was also reduced, but to a lesser extent, when the index finger was stimulated at painful levels Psychophysical studies using open magnitude scaling indicated that the relationship between stimulus intensity and perceived magnitude of electrical stimuli could be described by a power law with an exponent close to 10 Therefore, the percentage reduction in matching voltage accurately represents the percentage decline in perceived intensity These results suggest that the perceived intensity of cutaneous stimuli to the index finger over a range of intensities can be reduced by afferent activity from the hand The motor command appears to play a relatively minor role in modulating the perceived intensity