Showing papers by "University of Queensland published in 1976"

Australian middle cambrian molluscs and their bearing on early molluscan evolution

Abstract: Twenty-eight species of fifteen genera of Middle Cambrian molluscs are described from tiny phosphatic moulds or silica replicas of the shells. The molluscs were etched from limestones at two sites: one in the earliest Middle Cambrian Coonigan Formation of the Mootwingee area, 130 km northeast of Broken Hill, New South Wales; and another in the middle Middle Cambrian Currant Bush Limestone of the Thorntonia area, 150 km northwest of Mt Isa, Queensland. These unusually diverse collections show that many different kinds of molluscs lived in the tropical Australian seas of the Middle Cambrian and provide new information on the way the molluscan classes Cephalopoda, Gastropoda, Rostro- conchia, and Pelecypoda evolved. In other sections, we discuss the problems of classifying and naming Cambrian molluscs; define a number of terms that can be used to describe shell form (including a new adjective, gyrogastric); reclassify the Class Monoplacophora after incorporating the helcionellacean and bellerophontacean “gas...

Two-way pattern analysis of a large data set to evaluate genotypic adaptation

Abstract: A method for the analysis of genotype x environment interaction in large data sets is presented and applied to yield data for 49 wheat cultivars grown in each of 63 international environments. Pattern analysis using numerical classification defined separately groups of cultivars and groups of environments, based on similarities in yield performance. The group structure for cultivars was interpreted in terms of similarities and differences in cultivar mean yield and/or cultivar yield response patterns across environments. In addition, the cultivar groups reflected differences in genetical and selectional origin. Environment groups largely reflected differences in the average mean yield of the set of cultivars, but some groups showed differences in response patterns related to differential rust incidence.

Studies of the rosette inhibition test in pregnant mice: evidence of immunosuppression?

Abstract: The rosette inhibition test has been utilized as a measure of immunosuppression following organ transplantation, and we have recently demonstrated that it can also be used in detecting a state of depression of lymphocyte reactivity occurring in pregnant mice. If the depression of lymphocyte reactivity provides an indication of immunosuppression, then this study has shown that, in the mouse, the spleen lymphocytes are immunosuppressed as early as 4 h after fertilization. This state persists for 13-15 days, with a return to normal 4-6 days before full term. A similar depression of normal spleen lymphocytes can be induced in vitro by incubating these lymphocytes with serum taken from pregnant mice 6 and 24 h after mating. The serum factor detected was shown to be stable when heated at 56 degrees C but not at 72 degrees C, and to be non-dialysable. It was detected in serum to a dilution of 1 in 64. Further work is being undertaken to investigate this phenomenon and to pursue the purification and identification of the pregnancy factor.

Freshwater drowning and near-drowning accidents involving children: a five-year total population study

Abstract: A large total population study of childhood fresh water immersion accidents is reported. The study was undertaken in the City of Brisbane over the five-year period 1971 to 1975 inclusive, and 111 fresh water immersion accidents involving children were studied and analysed. The childhood fresh water immersion accident rate, including drowning and near-drownings, of 10-43 per year per 100,000 at risk (fatality rate of 5-17) is the highest reported. If an unsupervised child gets into difficulties in fresh water and loses consciousness he has a 50% chance of dying. The immersion accident rate has doubled over the last six years. Age-specific immersion accident rates have been calculated, and have revealed that, in the toddler group (12 months to 23 months), the fresh water immersion accident rate is 50-01 per 100,000 (fatality rate of 22-55). Rates for drowning and near-drowning accidents after a fresh water immersion, by site, age and outcome (survival versus fatality), are also presented for the first time. Swimming pools produce 6-20 immersion accidents per year per 100,000 children at risk, and the domestic family bath tub produces 1-78. Possible factors explaining the high incidence are discussed, and comparisons of drowning rates from other centres are made.

A comparison of alternative means of providing sensory feedback on upper limb prostheses

Abstract: Sensory feedback has been used, by a number of workers, to inform the central nervous system of the present state of an artificial limb. Although both electrical stimulation and electromechanical vibrations have been used, there appears to be no evidence of a direct comparison of the advantages and disadvantages of these methods. Such a comparison is made here. It is shown that the information transmission capabilities of both systems are more or less identical. The electrical system has some advantages in reducing the number of items in a myoelectric control system with feedback, but the mechanical vibration system has the advantage of a universal psychological acceptance. Crosstalk prohibits the use of two electrical feedback, channels and it is recommended that, where two channels are required, one should be electrical and the other a mechanical vibration.

Local oedema and general excitation of cutaneous sensory receptors produced by electrical stimulation of the saphenous nerve in the rat

Abstract: Recordings were made from multifibre strands of the saphenous nerve of rats anaesthetized with urethane and given Evan's blue intravenously. Stimulation of A plus C fibres of the saphenous nerve, but not A fibres alone, at 10 Hz for 5 min produced dye leakage in the skin of the hind limb. Stimulation of the nerve at A plus C fibre voltages with the stimulating electrodes placed distal to the recording electrodes produced reversible block of nerve impulses at the stimulating electrodes. However, when the stimulating electrodes were placed proximal to the recording electrodes, stimulation of the nerve at A plus C fibre voltages, but not at A fibre voltages, produced an increase in activity in nerve strands. An increase in activity was also observed in experiments where the contralateral saphenous nerve was stimulated. These effects were not abolished by pretreatment of rats with reserpine. The early phase of the local oedema response appeared to be reduced by local pretreatment with compound 48 80 but the excitatory action on nerve terminals was not. The effects of nerve stimulation were not mimicked by intravenous injection of 5HT, ATP or adenosine into the contralateral saphenous vein. It is suggested that several substances might be released on antidromic stimulation of C fibres and that the resulting general excitation of sensory nerve terminals might play a role in modifying the central nervous system response to nociceptive information.

Evolutionary consequences of eating:Trichosurus vulpecula (marsupialia) and the genusEucalyptus

Abstract: While being somewhat specialized on a diet of matureEucalyptus leaves (66% of feeding time), wildTrichosurus vulpecula consume an average of three different foods per night. Usually, these foods are two different species ofEucalyptus leaves, and “ground feeding.” Laboratory feeding experiments indicate that this ingestion of a variety of foods is due to severe limitations on the quantity ofEucalyptus leaves a possum is capable of consuming. It is argued that the limitation is due to plant toxins (volatile oils, phenols) present inEucalyptus leaves, rather than to “normal” nutritional factors. We hypothesize thatEucalyptus toxins indirectly regulate possum populations at levels that afford theEucalyptus trees some degree of protection from possum predation. In addition, we suggest that the “New Zealand phenomenon” can be explained by a lack, and acquisition, of plant chemical defenses against herbivores introduced from chemically more complex environments.

Metal ions in enzymes using ammonia or amides

Abstract: In an attempt to understand the role of nickel in jack bean urease (1), we turned to a variety of other enzymes important in the utilization, production, or transfer of ammonia. We found several, including the L-histidine and L-phenylalanine ammonialyases and some enzymes that utilize glutamine or ammonia in amidotransferase reactions, all of which show evidence for the involvement of as yet unreported transition metal ions in their mechanism of action. We support the view that catalysis by metalloenzymes may be a reflection of the chemistry of the metal ion itself as a Lewis acid, and that perhaps too much emphasis has been placed on supposed special characteristics (such as strains, "entasis") of the enzyme-metal ion association. In this context, we have discussed the mechanism of catalysis of hydrolysis of specific substrates by carboxypeptidase A, and have returned to urease to examine the role of nickel in its mechanism of action.

Designing Successful Classroom Environments for Different Types of Students

Abstract: * This paper is drawn from a more comprehensive report: Differential Strategies for Classroom Success: A theoretical model (Technical Report No. 100, Centre for Research in Social Behaviour, University of Missouri). This larger report is available upon request from Professor Thomas L. Good, Centre for Research in Social Behaviour, in East Stewart Road, University of Missouri, Columbia, Mo. The research was supported, in part, by the National Institute of Education Grant NEG‐00‐3‐0123. The opinions expressed herein do not necessarily reflect the position or policy of the National Institute of Education and no official endorsement from that office should be inferred. General support was also provided by the Centre for Research in Social Behaviour. The authors gratefully acknowledge the typing support of Peggy Bodine and Sherry Kilgore.

Purification, Properties and Immunological Relationship of l(+)-Lactate Dehydrogenase from Lactobacillus casei

Abstract: The fructose-1,6-bisphosphate-activated L-lactate dehydrogenase (EC 1.1.1.27) from Lactobacillus casei ATCC 393 has been purified to homogenity by including affinity chromatography (cibacronblue-Sephadex-G-200) and preparative polyacrylamide gel electrophoresis into the purification procedures. The enzyme has an Mr of 132000-135000 with a subunit Mr of 34000. The pH optimum was found to be 5.4 insodium acetate buffer. Tris/maleate and citrate/phosphate buffers inhibited enzyme activity at this pH. The enzyme was completely inactivated by a temperature increase from 60 degrees C to 70 degrees C. Pyruvate saturation curves were sigmoidal in the absence of fructose 1,6-bisphosphate. In the presence of 20 muM fructose 1,6-bisphosphate a Km of 1.0 mM for pyruvate was obtained, whereas fructose 1,6-bisphosphate had no effect on the Km of 0.01 mM for NADH. The use of pyruvate analogues revealed two types of pyruvate binding sites, a catalytic and an effector site. The enzyme from L. casei appears to be subject to strict metabolic control, since ADP, ATP, dihydroxyacetone phosphate and 6-phosphogluconate are strong inhibitors. Immunodiffusion experiments with a rabbit antiserum to L. casei lactate dehydrogenase revealed that L. casei ATCC 393 L (+)-lactate dehydrogenase is probably not immunologically related to group D and group N streptococci. Of 24 lactic acid bacterial strains tested only 5 strains did cross-react: L. casei ATCC 393 = L. casei var. rhamnosus ATCC 7469 - L. casei var. alactosus NCDO 680 greater than L. casei UQM 95 greater than L. plantarum ATCC 14917.

Plasma Level Monitoring of Anticonvulsants

Abstract: The plasma concentrations of anticonvulsant drugs, and of certain of their biologically active metabolites, tend to be proportionate to the antiepileptic effects of these drugs. Consequently, anticonvulsant drug levels in plasma are monitored to help guide the clinician in managing his patients’ epilepsies. In making use of the measurements, the clinician needs to know the relation between plasma level and biological effect for the various drugs. He also needs to have some awareness of simple pharmacokinetic principles. These are important in deciding when plasma levels should be monitored in relation to the patients’ clinical state, to the dosage interval, and to change in the dosage of anticonvulsant or other drug. The clinician also requires pharmacokinetic knowledge in altering anticonvulsant drug dosage in his patients, and in interpreting plasma anticonvulsant level data, particularly when the patient is concurrently suffering from non-neurological disease. The ability to monitor plasma anticonvulsant levels has appreciably improved the treatment of epilepsy, but to obtain maximum benefits from the method, both pharmacokinetic insight and clinical wisdom are required.

Asset pricing in the Australian industrial equity market

Abstract: The two-moment, mean-variance model of asset pricing is tested against data from the Melbourne stock exchange The model appears to describe the data quite well, though there are problems in experimental design which are yet to be cleared up Neither variance nor skewness appears to explain additional price behaviour to that explained by covariance, as is predicted by the two-moment model

Seismic Investigation of the Papuan Ultramafic Belt

Abstract: Seismic survey data from a profile along the north‐east Papuan peninsula coast indicate velocities which can be correlated with those of oceanic layers 1, 2 and 3, but with a crustal thickness of between 20 and 25 km. Distinct differences in the crustal layering are determined between the region where the Papuan Ultramafic Belt crops out along the coast and the region of the Trobriand Platform. The crustal thickness is more than twice the total thickness of gabbro and basalt components of the ophiolite suite exposed inland. Later seismic arrivals suggest the presence of a low‐velocity zone below the Moho and a return to upper mantle velocities at depths of about 50 km.

Iron Absorption in the Rat: The Search for Possible Intestinal Mucosal Carriers

Abstract: SUMMARY. The biological relevance of four iron-containing fractions previously detected in rat intestinal mucosal cells has been studied. The distribution of iron in these fractions obtained by chromatography on Sepharose 6B has been examined after in vivo and in vitro incubation of mucosal cells with 59Fe. In addition, the effects of phenobarbitone, cycloheximide, iron-deficiency and iron-loading on the uptake and distribution of iron within the four mucosal cell fractions was studied. The iron in fraction I was mostly bound to intracellular membrane particles. Fraction II was shown to be ferritin. Fraction III contained some transferrin and also a protein of molecular weight similar to transferrin but which was not precipitable by antitransferrin antiserum. Quantitative differences between the in vivo and in vitro studies combined with the results of ‘chaser’experiments suggested that, in addition to ferritin, at least two of the fractions (I and III) were involved in the process of iron absorption by the mucosal cell.

A theory of microwave lineshifts

Abstract: The Anderson theory of pressure broadening of spectral lines in the microwave region (1949) is extended to permit calculations of the shifts of spectral lines The extension is based on the analytic evaluation of double integrals Mathematical details are presented for the dipole-dipole, dipole-quadrupole and quadrupole-quadrupole interactions The theory is used to calculate the widths and shifts, over a temperature range from 150K to 500K, of the ammonia J=K=3-8 inversion lines perturbed by NH3, COS and CH3Cl, and of the self-perturbed CH3Cl(J=0 to 1) and COS(J=1 to 2) rotational lines

A petrological study of the younger Tongan andesites and dacites, and the olivine tholeiites of Niua Fo'ou Island, S. W. Pacific

Abstract: Basaltic andesites are the dominant Tongan magma type, and are characterized by phenocrysts of augite, orthopyroxene (or rarely pigeonite), and calcic plagioclase (modally most abundant phase, and interpreted as the liquidus phase). The plagioclase phenocrysts exhibit slight oscillatory reverse zoning except for abrupt and thin more sodic rims, which are interpreted to develop during eruptive quenching. These rim compositions overlap those of the groundmass plagioclase. The pyroxene phenocrysts also exhibit only slight compositional zoning except for the outermost rim zones; the compositions of these rims, together with the groundmass pyroxenes, vary throughout the compositional range of subcalcic augite to ferroaugite through pigeonite to ferropigeonite, and are interpreted in terms of quench-controlled crystallization. This is supported, for example, by the random distribution of Al solid solution in the groundmass pyroxenes, compared to the more regular behaviour of Al in the phenocryst pyroxenes. The analysed Niua Fo'ou olivine tholeiites are aphyric; groundmass phases are plagioclase (An17-88), olivine (Fa18-63), titanomagnetite (usp. 59-73), and augite-ferroaugite which does not extend to subcalcic compositions; this is interpreted to be due to higher quenching temperatures and lower viscosities of these tholeiites compared to the basaltic andesites. Application of various geothermometers to the basaltic andesites suggest initial eruptive quenching temperatures of 1,008-1,124 ° C, plagioclase liquidus temperatures (1 bar) of 1,210-1,277 ° C, and orthopyroxene-clinopyroxene equilibration of 990-1,150 ° C. These calculated temperatures, together with supporting evidence (e.g. absence of olivine and amphibole, liquidus plagioclase, and plagioclase zoning patterns) are interpreted in terms of phenocryst crystallization from magmas that were either strongly water undersaturated, nearly anhydrous, or at best, water saturated at very low pressures (< 0.5 kb). This interpretation implies that these Tongan basaltic andesites did not originate by any of the currently proposed mechanisms involving hydrous melting within or above the Benioff zone.

Primary cutaneous melanoma: a report from the Queensland melanoma project.

Abstract: generally regarded as a particularly viru lent and usually fatal disease, a reputa tion no longer deserved. If individuals are instructed to report any change in a mole, and if physicians are alert to the possibility of melanoma,* the diag nosis can be made at an early biologi cal and potentially curable stage. In Queensland, Australia, there are few major cancers that have as hopeful a prognosis. From 1963 through 1968, all cases of malignant melanoma occurring in Queensland were registered at the Re search Unit of the Princess Alexandra Hospital in Brisbane as part of the Queensland Melanoma Project.' Mi croscopic diagnoses were reviewed by a panel of pathologists, whose agree ment was required before the case was considered proven. More than 1,500 patients with malignant melanoma have been recorded, and form the basis of this article. In Queensland, the average annual incidence rate per 100,000 population was 14 for males and 17 for females, an average annual rate of 16 new pa tients per 100,000 population.2 This is the highest reported incidence in the world. No aborigines have been treated for melanoma in Queensland since the study began. No marked predilection was found in persons with a fair com plexion, blue eyes, blond or red hair.2 Unlike squamous cell carcinoma, no particular concentration of melanoma on exposed sites was noted.2 An environmental factor is probably responsible for the high incidence of malignant melanoma in Queensland; sunlight is the most likely etiologic agent, and possibly exerts both a direct and an indirect effect on the develop ment of this skin cancer.3

Influence of weather and nocturnal illumination on the activity and abundance of populations of Noctuids (Lepidoptera) in south coastal Queensland

Abstract: A light-trap separating hourly catches was operated on a pasture research station in south coastal Queensland for 18 months in 1972 and 1973. A total of 339 000 Noctuid moths was captured. Half of the catch comprised pest species. Weather and nocturnal illumination were recorded on the trapping site. Multiple regression analyses were performed on the raw data, and, for comparison, some pest species were reared under semi-field conditions for a year. Night temperature, night wind and nocturnal illumination, in that order, were the most important factors influencing catch. Temperature and wind were each responsible for about one-fifth of the variance in catch, nocturnal illumination for about one-tenth. Twenty per cent of the variance in catch cannot be ascribed to changes in local weather or illumination. Wind had a significantly stronger influence on males than on females all year round, temperature a significantly stronger one on females than on males in summer. This was probably due to differences in the vertical distribution of flight in the two sexes, females flying lower than males. Nocturnal illumination had a significantly stronger influence on females than on males; on females its influence was almost as strong as that of wind, increasing with rising temperature to be twice as strong in summer as in winter. Females were most abundant in the first part of the night, males in the second. Temperature, wind and moonlight maintain this nocturnal distribution which is probably endogenously controlled. Female flight is probably linked to oviposition, male flight to response to pheromone release from calling females. Heavy out-of-season rainfall had a negative effect on Noctuid populations in the area and strongly increased both larval and adult mortality. Temperatures and rainfall during the larval and adult periods equal to the corresponding long-term averages and totals create optimal conditions for the development of Noctuid populations. Strong indications of migration were found in autumn and spring of 1973. Many moths of different species probably entered the area during nights with wind convergence caused by the passage of cold fronts. Separate analyses on the most abundant pest species confirmed the results of the analyses on the total catch of Noctuids.

Tensile deformation behaviour of ABS polymers

Abstract: Several grades of ABS polymer have been tested in uniaxial tension over a temperature range from 293 K (20° C) to 198 K (−80° C). Effects of strain-rate and temperature on the yield stress have been explored and the magnitude of the activation volumes and activation energies derived. Additionally, the volume strain and the longitudinal strain have been monitored simultaneously, from which data the contribution of crazing to the total deformation of the specimens has been obtained.

THE CONTRIBUTION OF EXTRANEURONAL UPTAKE TO THE TRACHEA‐BLOOD VESSEL SELECTIVITY OF β‐ADRENOCEPTOR STIMULANTS in vitro IN GUINEA‐PIGS

Abstract: 1 The potencies relative to isoprenaline of isoetharine, tertiary butyl noradrenaline, salbutamol, orciprenaline, Me 506, rimiterol, fenoterol, carbuterol and terbutaline on isolated preparations of guinea-pig trachea and blood vessels (perfused hind limb) were determined. All the compounds were selective for trachea and selectivity values, i.e. relative potency on trachea divided by relative potency on hind limb, ranged from 2.3 to 21.4. 2 Responses to isoprenaline (the reference compound), tertiary butyl noradrenaline and isoetharine were potentiated on trachea by 50 muM phenoxybenzamine (PHB) and by other inhibitors of extraneuronal uptake (ENU). Under these conditions the selectivity values of all the compounds was close to unity. 3 Selectivity values were also close to unity if they were calculated from data obtained without ENU inhibition, provided that only those compounds not potentiated by PHB on trachea were used. 4 It is proposed that the trachea-blood vessel selectivity shown by beta-adrenoceptor stimulants can be caused by the influence of ENU upon them, rather than by their ability to distinguish between two beta2-adrenoceptors. 5 The suggestion that differences exist between beta2-adrenoceptors in respiratory and vascular smooth muscle is not supported by the in vitro experiments described.