Showing papers by "University of Western Australia published in 1968"
TL;DR: In this article, a series of 0·5 molal Fe(III) hydroxide gels were produced by aging the gels at 60°C in the presence of excess NaOH and examined qualitatively by electron microscopy, selected area diffraction and X-ray diffractometry.
238 citations
TL;DR: Injections of glucagon, adrenalin and noradrenalin into the rat foetus in utero result in development of phosphopyruvate carboxylase activity, which appears to be due to enzyme synthesis in neonatal rat liver.
Abstract: 1. Phosphopyruvate carboxylase activity rapidly appears in the liver of prematurely delivered rats and development of activity is prevented by injection of actinomycin D just before delivery. 2. The activity is considerably decreased by puromycin and amino acid analogues and thus appears to be due to enzyme synthesis. 3. Newborn or premature animals show a transient intense phase of hypoglycaemia after delivery. 4. When the hypoglycaemic phase is prevented by glucose injection little phosphopyruvate carboxylase activity appears in the liver, but galactose, mannose and fructose, which have no effect on the blood glucose concentration, also repress enzyme development. 5. Lactate, pyruvate and glycerol injections repress the premature development of phosphopyruvate carboxylase. 6. Injections of glucagon, adrenalin and noradrenalin into the rat foetus in utero result in development of phosphopyruvate carboxylase activity. 7. These findings are discussed in relation to the mechanism of initiation of enzyme synthesis in neonatal rat liver.
115 citations
TL;DR: Serological data, and the information about phylogeny which they supply, can be used as the basis of a revised classification of the Marsupialia.
Abstract: Serological data, and the information about phylogeny which they supply, can be used as the basis of a revised classification of the Marsupialia.
100 citations
TL;DR: The plasma corticosterone concentrations in foetal rats are as high as six times maternal values at day 19 of gestation and are approximately equal to maternal values from day 20 to term and in postnatal rats over the first few hours after delivery.
Abstract: 1 Plasma corticosterone concentrations were determined in the foetal rat during the gestational period from day 18·5 to term and in postnatal rats over the first few hours after delivery 2 The plasma corticosterone concentrations in foetal rats are as high as six times maternal values at day 19 of gestation and are approximately equal to maternal values from day 20 to term 3 In postnatal rats the plasma corticosterone concentrations rise 3·5-fold on average within 5hr of delivery 4 The results are discussed in relation to the function of adrenal steroids in postnatal liver development
99 citations
TL;DR: The thermodynamic properties of the noninteracting Bose gas in the neighborhood of its transition are examined in detail in this paper, where the correlation function in the critical region is a homogeneous function of the distance and a correlation length.
Abstract: The thermodynamic properties of the noninteracting Bose gas in the neighborhood of its transition are examined in detail. The order parameter is a complex extensive variable, but the thermodynamic properties depend only on its amplitude under simple boundary conditions. As the dimensionality or the single-particle energy spectrum is varied, the critical singularity displays a variety of forms. The equation of state has a simple structure, different from the homogeneous form often discussed for critical systems but asymptotically reducing to the latter except when logarithmic singularities are involved. The correlation function in the critical region is a homogeneous function of the distance and a correlation length. Only for a quadratic energy spectrum is the Ornstein-Zernike theory result valid at the critical temperature. A precise correspondence is noted between the asymptotic properties of the ideal Bose gas transition and those of the spherical model of ferromagnetism.
99 citations
TL;DR: Two studies with an ancient memory system demonstrate that capacity in serial learning tasks and paired associate tasks is raised and it is also shown that serial position effects and proactive inhibition effects are notably absent.
Abstract: Two studies with an ancient memory system demonstrate that capacity in serial learning tasks and paired associate tasks is raised by at least an order of magnitude. It is also shown that serial position effects and proactive inhibition effects are notably absent. Performance of normal Ss using the memory system is compared with a reported case of exceptional memory.
91 citations
TL;DR: The contribution of discrete behavioural attitudes towards temperature regulation has been studied, both in the field and in the laboratory, in five species of Agamid lizards of the genus Amphibolurus as mentioned in this paper.
Abstract: The contribution of discrete behavioural attitudes towards temperature regulation has been studied, both in the field and in the laboratory, in five species of Agamid lizards of the genus Amphibolurus. This genus has radiated widely in the arid and semi-arid areas of Australia and the species selected for study were chosen to represent, as closely as possible, the range of habitats occupied by the genus. Behaviour patterns thought to be of significance in temperature regulation have been characterized thermally in terms of the mean body temperature and the set of mean environmental temperatures at which they have been observed. When comparisons are made between the temperature specificities of similar and analogous behaviour patterns displayed by species from different habitats, few significant differences emerge. Thus, desert-living species show no greater tolerance towards grossly elevated body temperatures than do species from less severe habitats, when similarly temperature acclimated, although the former are exposed daily to environmental temperatures much greater than those prevailing in semi-arid and sub-humid habitats. Selection for the ability to tolerate increased body temperatures therefore does not appear to have operated in the genus, due to the efficacy of the thermoregulatory behaviour of these lizards. All species, however, depend upon the presence of thermal refuges for their survival during the hottest periods of the day, and this is especially so for species inhabiting very hot dry habitats. Desert-inhabiting species are also obliged to spend considerable periods of the day in high-temperature avoidance behaviour patterns and are thus forced to endure long daily exposures to body temperatures above those preferred for activity. Short-term acclimatory adjustments in temperature tolerance assist the animals in surviving this exposure. The situation with Amphibolurus contrasts strongly with that found in other desert-living agamids, such as Diporophora, which are unable to avoid effectively the heat of the day and show an ability to tolerate high body temperatures far in excess of the most thermophilic Amphibolurus species.
83 citations
TL;DR: In this paper, the authors reported the intensity and frequency data for the 2800 A transitions of 9 ketones and 5 nitroparaffins in the vapour and in 11 solvents.
78 citations
TL;DR: In this paper, it was shown that diffuse double theory is completely inadequate for describing swelling of calcium saturated clays and for predicting the pore solution composition, and the use of chloride exclusion measurements to provide information on the nature of particle interaction was discussed.
Abstract: Particle interaction discussed in this paper may be limited, in which contiguous interacting plate shaped particles are within 10 A of each other, or extensive, in which surface separations exceed 40 A. Extensive swelling is caused by the interaction of Gouy-Chapman diffuse double layers and the conditions under which diffuse double layer theory can be used to describe extensive swelling are re-viewed. The essential feature of extensive swelling is its dependence on electrolyte concentration.
X-ray studies of the variation of d(001) spacings for montmorillonite and vermiculite when saturated with divalent and large monovalent ions have been discussed as examples of limited swelling. This behaviour is contrasted with sodium montmorillonite which exhibits extensive crystalline swelling for concentrations less than 0.3 M NaCl.
The similarity of the swelling behaviour of a montmorillonite crystal and of a parallel assemblage of crystals constituting a domain has been noted and presented as an argument for domains being regarded as particulate entities in calcium saturated clay materials.
The limited crystalline swelling of calcium montmorillonite and domain swelling of calcium saturated clays is little affected by electrolyte concentrations less than molar. The inter-crystalline swelling which occurs in soils and clay materials is triggered off by the adsorption of two layers of water; the adsorption of the two layers of water at areas of crystal overlap release mechanical energy stored as a result of crystal bending and packing on the drying cycle. This release of mechanical energy creates pores in which liquid is held by surface tension forces as distinct from water held at the clay solution interface by hydration and osmotic forces.
The use of chloride exclusion measurements to provide information on the nature of particle interaction is discussed. The information presented on domain structure and ion distribution at interfaces, as deduced from chloride exclusion measurements, reveals that diffuse double theory is completely inadequate for describing swelling of calcium clay systems and for predicting the pore solution composition.
72 citations
TL;DR: Some of the ambiguities and confusion in the present use of the concept of nutrients are discussed, and more precise descriptions of the relations between nutrients and growth of plants are proposed.
Abstract: Nutrient requirement is a simple and useful concept when used in a qualitative sense, but it is much less satisfactory for quantitative comparisons among organisms. Some of the ambiguities and confusion in the present use of the concept are discussed, and more precise descriptions of the relations between nutrients and growth of plants are proposed.
72 citations
TL;DR: Evidence of a high “pressure” towards paradoxical (REM) sleep at the expense of Stage II sleep is shown in two healthy men who normally sleep only about 3 h per 24.
TL;DR: This chapter emphasizes on peculiarities of distribution, life history, and ecology of Australian frogs in terms of their evolutionary history.
Abstract: Publisher Summary This chapter emphasizes on peculiarities of distribution, life history, and ecology of Australian frogs in terms of their evolutionary history. Environmentally, Australia is characterized by a central desert, which with the adjacent semi-arid areas accounts for about 70% of the area of the continent. Well-watered areas occur only in the southwest, south-east, east, and north regions. It is noted that frogs can occur in the desert despite the low rainfall. They survive because they can make use of water when it is present, and so breed and feed. When water is not present they avoid the aridity usually by burrowing. In context to breeding biology, females enter the breeding sites in late autumn to lay unpigmented eggs in a frothy mass in a burrow, specially excavated by the male, at a site which can later be flooded by winter rains. The breeding is unrelated to rainfall or temperature conditions. When rain floods the low-lying breeding sites no further egg laying occurs.
TL;DR: The results are discussed in relation to current hypotheses on the role of hormones in enzyme induction in foetal development and the premature induction of activity is completely repressible by actinomycin D given soon after delivery and partially repressedible by puromycin and amino acid analogues.
Abstract: 1. Premature delivery of foetal rats by uterine section results in the rapid appearance of tyrosine aminotransferase activity in foetal liver, after an initial lag period of 3-6hr. 2. The premature induction of activity is completely repressible by actinomycin D given soon after delivery and partially repressible by puromycin and amino acid analogues. 3. Glucagon injections into foetal rats in utero lead to production of tyrosine aminotransferase in the foetal liver, but adrenalin and nor-adrenalin are without effect. 4. Injections of glucose, galactose, fructose and mannose into prematurely delivered rats repress the development of tyrosine aminotransferase activity about 50% when they are given 2hr. after delivery, but glucose has no significant effect when injected at delivery. 5. The results are discussed in relation to current hypotheses on the role of hormones in enzyme induction in foetal development.
TL;DR: From a study of the effects of Ca ions on the nodulation of subterranean clover in flowing culture solutions it is concluded that root infection or nodule initiation has a higher Ca requirement than either nodule development or host plant growth in the presence of fixed nitrogen.
Abstract: From a study of the effects of Ca ions on the nodulation of subterranean clover in flowing culture solutions it is concluded that root infection or nodule initiation has a higher Ca requirement than either nodule development or host plant growth in the presence of fixed nitrogen.Increasing Ca concentration from 246 to 720 mum had no effect on growth of the host plant but increased the number of nodules from 7 to 24 per plant. Decreasing Ca concentration from 246 to 4 mum progressively decreased both plant growth and nodule numbers.It is suggested that nodule infection or initiation required higher solution concentration of Ca than nodule development since transferring plants after 10 days in lower Ca treatments to 720 mum Ca for 7 days did not increase nodule numbers above those on plants treated continuously at low Ca. Similarly transferring plants from 720 mum Ca to lower Ca treatments did not decrease nodule numbers much below those on plants grown continuously at 720 mum Ca even though growth was depressed. Once initiated, nodule development proceeded at concentrations of Ca too low for plant growth.The high Ca requirement for root infection or nodule initiation was not thought to be due to effects on survival or growth of Rhizobium and could not be related to effects of Ca on a number of relevant processes:-tap root length, root hair development, or lateral root initiation.
TL;DR: When a tsunami wave series approaches and interacts with a coast, the consequent passage shorewards of great volumes of water and their invasion of the land, especially within bays and up river valleys, results in the disturbance of existing sediment and the removal seawards of land debris and coastal and shallow-water marine sediments as mentioned in this paper.
Abstract: When a tsunami wave series approaches and interacts with a coast, the consequent passage shorewards of great volumes of water and their invasion of the land, especially within bays and up river valleys, results in the disturbance of existing sediment and the removal seawards of land debris and coastal and shallow‐water marine sediments. Tsunami action builds up sequences of peculiar sediments in shallow water; it at least assists in the formation and maintenance of submarine canyons and, through them, produces turbidity currents of a particularly powerful kind. Tsunami action may explain many puzzling sedimentary phenomena, for example, sudden and drastic changes in near‐shore bathymetry; the formation of chaotic sediments such as some paraconglomerates and edgewise conglomerates. It offers solutions to problems arising from the study of turbiditic sequences, both modern and ancient.
TL;DR: It is concluded that gibberellins are normally involved in regulating growth in green and brown algae.
Abstract: Gibberellin-like activity was detected in extracts from Enteromorpha prolifera (Chlorophyta) and Ecklonia radiata (Phaeophyta). Material eluted from chromatograms of extracts and active in dwarf maize also brought about growth responses in the species from which the extract had been made. The responses were similar to those brought about by gibberellic acid. It is concluded that gibberellins are normally involved in regulating growth in green and brown algae.
TL;DR: Smoking or exposure to urban air pollution, quartz dust, or the British climate is calculated to add 5-10, 10, 10%, 10%, and 10-20% to the prevalence-rates of chronic bronchitis among people not exposed to these factors.
TL;DR: It is suggested that, at the low concentrations of K and Ca likely to be found at the root surface in many soil solutions, the above mentioned effect of K in inhibiting Ca absorption may be important in the Ca nutrition of plants.
Abstract: Increasing concentrations of K (20, 200, 2000 mum) in the nutrient solution depressed Ca content and concentration in barley plants growing in nutrient solutions of low Ca concentrations (250 and 2500 mum). Increasing K from 20 to 200 mum depressed Ca absorption more than increasing K from 200 to 2000 mum K.The strong depression of Ca absorption by low concentrations of K must involve a different process from that studied by other workers at high concentrations of K. Since the depression in net absorption of Ca was as great at 250 as at 2500 mum Ca the results fail to support previous suggestions that a specific mechanism for Ca absorption operates at low Ca concentrations. It is suggested that, at the low concentrations of K and Ca likely to be found at the root surface in many soil solutions, the above mentioned effect of K in inhibiting Ca absorption may be important in the Ca nutrition of plants.
TL;DR: The part played by the eyes in the light-dependent behaviour of the scorpion was investigated and the spectral sensitivity of this light response was determined.
TL;DR: In this paper, an experimental study has been made of the external and internal structure of artificial hailstones grown freely supported in a vertical wind tunnel at airspeeds of 35 to 40 m s−1.
Abstract: An experimental study has been made of the external and internal structure of artificial hailstones grown freely supported in a vertical wind tunnel. In addition the nature of ice deposits formed on fixed stationary objects and objects rotating about a horizontal axis has been investigated at airspeeds of 35 to 40 m s−1. Lobe-like growth similar to that found in natural hailstones has been reproduced. The lobes are most pronounced when the accreted droplets are small and when growth takes place near the wet limit. With large droplets and when the growth is very spongy the surface irregularities are far less marked. It is inferred that the lobe-like growth is due to a collection efficiency effect.
The drag coefficients of a number of artificial hailstones have been measured. None of the values is greater than 0·66. Some of the moderate sized stones (4 to 6 cm diameter) entered the critical flow regime where their drag coefficients were considerably reduced. This did not occur, however, for large (10 cm diameter) very irregular hailstones.
TL;DR: In this paper, the authors measured the component velocities parallel to and normal to the basal plane of ice growing in supercooled water and aqueous sucrose solutions at supercoolings up to 10°C.
Abstract: Measurements have been made of the component velocities parallel to and normal to the basal plane of ice growing in supercooled water and aqueous sucrose solutions at supercoolings up to 10°C. It has been found that there are discontinuities in the velocity curves for the sucrose solutions. It is inferred that these are due to a growth mechanism change.
TL;DR: In this article, the authors show that selective pressure-solution of calcite in dolomitic limestone can cause relative enrichment in dolnite, and this allows speculation that the process can form pure dolombones from some dolnitic limestones.
Abstract: STUDIES of Western Australian stylolitic limestones reported here strongly support the widely held view that stylolites form by pressure-solution1–3, and agree with suggestions that pressure-solution can significantly reduce the volume of carbonate formations. Furthermore, these results indicate that selective pressure-solution of calcite in dolomitic limestone can cause relative enrichment in dolomite, and this allows speculation that the process can form pure dolomite rocks (dolostones) from some dolomitic limestones. Calcite is likely to be released for the cementation of nearby formations, and thinning in the limestone bodies may induce new structures in overlying strata.
TL;DR: The renal concentrating ability of the tammar, and other aspects of its water metabolism, are compared with eutherian mammals capable of drinking sea water or equivalent NaCl solutions and can concentrate urinary electrolytes to a greater degree than the kangaroo rat.
TL;DR: In excised roots of barley and tomato plants, lowering the water potential of nutrient solutions to-10.4 and-20.4 atm decreased the uptake of bromide and phosphorus while increasing the loss of these ions to the external solutions as discussed by the authors.
Abstract: In excised roots of barley and tomato plants, lowering the water potential of nutrient solutions to-10.4 and-20.4 atm decreased the uptake of bromide and phosphorus while increasing the loss of these ions to the external solutions.
TL;DR: The cuticle of the leaves of Nicotiana tabacum is covered with a gummy layer, some of which seems to originate as an exudate from the leaf hairs or trichomes as mentioned in this paper.
Abstract: THE cuticle of the leaves of Nicotiana tabacum is covered with a gummy layer, some of which seems to originate as an exudate from the leaf hairs or trichomes.
TL;DR: In this article, three aspects of the ice accretion process are considered and models of the freezing process are proposed and the freezing times of the droplets calculated theoretically, showing that even with low density rime deposits the deposit temperature is the prime factor in governing the freezing.
Abstract: Three aspects of the ice accretion process are considered. Firstly it is shown experimentally that, as the deposit temperature is raised, the individual droplets pack more closely giving a more compact and denser deposit. Models of the freezing process are then proposed and the freezing times of the droplets calculated theoretically. These calculations show that even with low density rime deposits the deposit temperature is the prime factor in governing the freezing. Finally, the statistical nature of the accretion process is considered and the probabilities of one or more droplets arriving and interfering with the freezing and cooling of an initial droplet are deduced.