Showing papers by "University of Adelaide published in 1971"

Flood Deposits of the Sand-Bed Ephemeral Streams of Central Australia

Abstract: This study investigates the deposits of sand-bed ephemeral streams within an area of 250,000 km2 in the western Lake Eyre basin, central Australia, being initiated after the record floods of February–March 1967. Large-scale ripples were the most common bed forms preserved in the majority of channels, covering 30–40% of the depositional area. Other bed forms included longitudinal, transverse and linguoid bars (20%), upper-regime plane beds (<5%), small-scale ripples (25–30%), and flute marks (<1%). Major bed forms could be related to flood stage: plane beds (upper regime), large-scale ripples, and longitudinal bars usually were generated by high-stage flow, and transverse and linguoid bars by waning and low-stage flow. Trough cross-stratification was produced by migrating small-scale and large-scale ripples, large-scale sets comprising about 60% of the deposits. Tabular cross-stratification (25% of deposits) resulted from the downstream and lateral growth of channel bars. Flat-bedding with parting lineation (<5%) was dominant only along the middle reach of the Finke, the major stream in the western Lake Eyre basin. Disturbed bedding was almost totally absent. Bed forms, in order of increasing overall mean grain size (?) of deposits, are plane beds (upper regime), small-scale ripples, transverse and linguoid bars, and large-scale ripples. Sorting (σI) and skewness (SkI) are dependent on mean grain size (Mz). Lower-regime flow prevailed for the majority of streams, upper-regime flow being dominant only in the middle reach of the Finke. Using estimated Froude numbers and Darcy-Weisbach resistance coefficients, the greatest mean velocities of flow have been calculated at about 0.8–3.7 m/sec.

Andean orogeny and ocean floor spreading.

Abstract: The periodicity and eastward migration of the Andean orogeny is explained in terms of periodic loss of marginal continental crust by crustal subduction.

Acquisition of virulence by non-pathogenic isolates of Agrobacterium radiobacter

Abstract: Tumours developed on tomato plants inoculated with Agrobacterium radiobacter var. tumefaciens biotype 2. When tumours were contaminated with the saprophyte, Agrobacterium radiobacter var. radiobacter biotype 1, the previously saprophytic bacterium became virulent. Acquisition of virulence was dependent on the efficiency of the recipients, on the duration of contact between saprophyte and tumour and on the stage of tumour development. A difference in the efficiency of the donors was not detected. There was no evidence for acquisition of virulence when the bacteria were mixed in liquid culture.

Factorization of the residual operator and canonical decomposition of nonorthogonal factors in the analysis of variance

Abstract: SUMMARY A factorization is given of the residual operator for nonorthogonal analysis of variance. It is interpreted geometrically in terms of the critical angles between the subspaces determined by the factors. The factorization determines a recursive procedure for analysis as described by Wilkinson (1970). Canonical components are defined and a method of computing them is given together with formulae for their variances, since these would be required for combining information, as for instance, in the recovery of interblock information.

Radiocarbon Dating of Arid-Zone Calcareous Paleosols

Abstract: Field study and radiocarbon dating of authigenic carbonate in arid-zone paleosols and calcretes have been carried out in Australia to determine the reliability of this method of soil dating. Three calcareous paleosols of late Quaternary age are developed within alluvial and eolian deposits on the Lake Torrens plain in arid South Australia. Dates for organic carbon obtained from the sediments show that soil-forming episodes took place shortly after 30,000 yrs B.P., between about 16,000 and 12,000 yrs B.P., and between 6,000 and 1,500 yrs B.P. Respective mean radiocarbon ages determined for pedogenic carbonate are (with approximate scatter) 27,450 (± 7,000) yrs B.P., 13,900 (± 2,000) yrs B.P., and 7,750 yrs (± 1,000) B.P. Although the great majority of the individual carbonate dates and the three mean dates are sound as relative ages, they are less reliable as absolute ages. A review of the literature reveals that most carbonate dates for arid-zone paleosols and calcretes which have been dated by coexisting organic carbon are from about 500 to 7,000 radiocarbon years too old. This is attributed to an initial low C 14 /C 12 ratio in soil carbonate, reflecting low C 14 content of source carbonate. Postformation contamination with C 14 commonly appears to be minimal in the arid zone, where dates for micritic carbonate from well-drained sites should approximate to or be up to several thousand years older than true ages of soil formation. Age correction based on δC 13 values for soil carbonate is invalid.

Cold Hypersensitivity in Raynaud's Phenomenon

Abstract: We have sought evidence that local cooling enhances the adrenergic neurotransmitter mechanism in resistance vessels in the hands of subjects with Raynaud's phenomenon. The method used was to examine the magnitude and time-course of the reflex vasoconstriction in the hand which follows application of ice to the neck. One hand of each subject was kept at 26°C and the other at 36°C, while the general thermal environment was varied. Enhancement was found in three groups of subjects: those with idiopathic, early age-onset, Raynaud's disease; those with Raynaud's phenomenon of late age-onset; and those with systemic scleroderma. It was absent in normal subjects. The effect could not be accounted for by structural abnormalities of resistance vessels, blood abnormalities, nor by interference with norepinephrine reuptake or dissipation at the neuro-effector junction.

Energy losses and modulation of galactic cosmic rays

Abstract: Galactic cosmic ray transport equation numerical solution for interplanetary region, considering modulation, diffusion, convection and energy loss effects

A Selective Medium for Agrobacterium radiobacter Biotype 2

Abstract: SUMMARY. A selective medium has been developed which allows a. quantitative estimation of numbers of Agrobacteriurn Tudiobacter biotype 2 in soil and in crown gall tissue. In the soils tested, both tumour inducing and saprophytic forms of biotype 2 occurred. A NEW TUMOUR INDUCING organism seems to be largely responsible for crown gall in at least 2 South Australian nurseries (Kerr, 1969; New, unpublished). Biochemical, serological and electrophoretic studies of the organism, Agrobacterium radiobacter var. turnefaciens biotype 2 (formerly designated Agrobacterium sp. (Kerr, 1969)), have shown it to be quite distinct from the traditional pathogen, A. tumefaciens, which is now designated A. radiobmter var. tumefaciens biotype 1 (Keane, Kerr & New, 1970). Ecological study of the crown gall bacteria has been limited by lack of a suitable selective medium. An excellent medium for most biotype 1 agrobacteria is available (Schroth, Thompson & Hildebrand, 1965), though it does not distinguish the tumorigenic bacterium from the non pathogen (A. radiobacter var. radiobacter biotype 1). A medium has now been developed for biotype 2 agrobacteria commonly found in South Australia.

Transmission of water waves through small apertures

Abstract: A method of solution is proposed for flows through small apertures in otherwise impermeable barriers. This method, which is an application of the method of matched asymptotic expansions, is used to solve a specific water-wave problem, yielding an approximate formula for the transmission coefficient.

Geographic Distribution and Time Range of the Ediacara Precambrian Fauna

Abstract: Occurrences of elements of the Ediacara fauna are known from ten different areas from strata of late Precambrian age. Those that have been dated isotopically are reported to be about 600 to 700 m. y. old.

The passage of cytoplasmic vesicles across endothelial and mesothelial cells.

Abstract: SUMMARY The proportions of labelled cytoplasmic vesicles, at increasing distances across mouse heart endothelium and diaphragmatic mesothelium, were studied using the following electron-microscopical tracers: ferritin, horseradish peroxidase and sodium ferrocyanide. The cells were incubated in Hank's solution containing the tracer for periods of 2 sec up to 30 min. Peroxidase labelled the vesicles well, but ferrocyanide may have escaped from them into the cytoplasm. Both passed down the intercellular junctions. Ferritin showed evidence of molecular sieving when entering the vesicles, and probably also suffered from this on leaving them. It was possible to allow for these effects. The vesicles containing tracers were found to have traversed the cells after only a few seconds; by approximately 10 sec a steady-state was observed, after which there were constant proportions of labelled vesicles. These proportions decreased slightly, but not sharply, across the cells. It was found that the observed distributions across the cells were very similar to those predicted by diffusion theory, assuming the following postulates: (1) the vesicles are moved solely by Brownian motion; (2) a low (i.e. α = 0.05) probability that a collision with a plasma membrane results in fusion. If however it was assumed that the fusion probability (α) were unity, the observed distributions of labelled vesicles differed very significantly from those predicted. A possible explanation of the observed low value of α is suggested, based on mutually-repelling charges on the vesicles and membranes. If α is given a value of around 0.05, the observations agree with calculated predictions that the median transit times for vesicles through cells 0.3–0.5 μm wide are approximately 3–5 sec and that the cytoplasmic viscosity is approximately 0.2–0.3 poise. The predictions of vesicular median free lives of- sec and median attachment times of 3–5 sec also received confirmation, as did the prediction that some 40% of the released vesicles regain the membrane on the opposite side of the cell.

Distribution of the lichen chondropsis semiviridis in relation to its heat and drought- resistance

Abstract: Summary The distribution of Chondropsis semiviridis (FvM. ex Nyl.) Nyl. was mapped for Australia. Studies in gas exchange physiology demonstrated that length of drought is likely to limit distribution of the species. Similarly, it is shown that sensitivity to heat when wet is likely to prevent the species from establishing in arid areas with a summer rainfall seasons The surge of respiration upon wetting of lichen thalli noted by other workers was so short for C. semiviridis that it could not affect the limits of its distribution.

Increase in number of synapses in the inner plexiform layer of light deprived rat retinae: quantitative electron microscopy.

Abstract: One eye in each of five adult Wistar hooded rats was covered with opaque contact occluders for three or nine months. The rat retinae were studied with light and electron microscopy. No changes in retinal thickness or in gross structure were seen. However, quantitative differences in synaptic organisation were found. (1) First comparison. A montage of a normal retina was compared with a similar montage of a three month lighted-deprived retina. Taking equal areas of inner plexiform layer, the number of amacrine (conventional) synapses in the light-deprived montage was larger by a factor of about 2.4 relative to the normal one. No significant difference in the number of bipolar (ribbon) synapses was found. (2) Second comparison. Samples were compared from five normal and five light-deprived retinae. The light-deprived retinae showed a significantly larger number of amacrine synapses compared with the normal mean (p<0.02). It was not possible to determine if the changes in synaptic number are related to changes in vesicle dimensions reported herein. The increased number of conventional synapses seems evidence that central nervous tissue is capable of forming new synapses without changing the organisation of neural processes.

Hierarchy of Water and Energy Turnover of Desert Mammals

Abstract: MAMMALS inhabiting desert regions might be expected to have similar physiology, particularly in rates of water use. Groups of ungulates in the field, however, show a wide range of water consumption. We measured, over periods of weeks, the uninhibited intake of water and food by groups of animals grazing together on the same territory and this was integrated with metabolic water from oxidation of hydrogen. Using this approach1 we found that buffalo (Bos bubalus bubalis) have the highest water turnover of any unstressed animal so far measured—200 ml./kg/24 h. Bos taurus in the same tropical climate were next in rank order, then Bibos banteng and the least water-demanding of the cattle group were Bos indicus (123 ml./kg/24 h). In the summer deserts of Australia and northern Kenya, the highest water turnover rates occurred in cattle, with sheep at about half their rate, goats somewhat less and camels (Camelus dromedarius) least in their water requirements, at half to one-third the rate of cattle2. In temperate environments the same rank order of genera and species was sustained. Because of different degrees of fatness (body solids, Table 1) it is useful to rank the animals by mol/l.0.82, which relates to the number of molecules passing through the size-adjusted volumes of body water.

Free products of topological groups

Abstract: In this note the notion of a free topological product Gα of a set {Gα} of topological groups is introduced. It is shown that it always exists, is unique and is algebraically isomorphic to the usual free product of the underlying groups. Further if each Gα is Hausdorff, then Gα is Hausdorff and each Gα is a closed subgroup. Also Gα is a free topological group (respectively, maximally almost periodic) if each Gα is. This notion is then combined with the theory of varieties of topological groups developed by the author. For a variety of topological groups, the -product of groups in is defined. It is shown that the -product, Gα of any set {Gα} of groups in exists, is unique and is algebraically isomorphic to the usual varietal product. It is noted that the -product of Hausdorff groups is not necessarily Hausdorff, but is if is abelian. Each Gα is a quotient group of Gα. It is proved that the -product of free topological groups of and projective topological groups of are of the same type. Finally it is shown that Gα is connected if and only if each Gα is connected.

On Ship Wave Patterns and Their Spectra

Abstract: The one-dimensional and two-dimensional spectra of a ship wave pattern have been derived. It is shown that the spectra have distinct signatures containing information on speed, direction, shape, size, and wave resistance of the ship. The speed and direction are readily determined but the relationship of the spectrum to other ship characteristics requires further investigation. Some examples of detailed wave patterns in the wake of a parabolic-sided ship have been computed.

Role of an isoacceptor transfer ribonucleic acid as an enzyme inhibitor: effect on tryptophan pyrrolase of Drosophila.

Abstract: IN this article a previous extrapolation of the 12C+12C reaction cross section is re-evaluated, in the light of new measurements of the 12C+16O reactions which suggest that the “quasi-molecular” resonances observed in these reactions do not contribute to the cross sections at the lowest energies.

Electron-impact studies—LX Negative-ion mass spectrometry of functional groups skeletal-rearrangements in aryl nitro compounds†

Abstract: The molecular anions of nitrobenzenes containing an electron-withdrawing substituent eliminate NO· via a skeletal rearrangement process in the order ortho > para > meta. An ortho substituted nitrobenzene may eliminate a neutral molecule after the loss of NO· Hydrogen-rearrange-ment processes, hydrogen-scrambling processes, and unusual concerted eliminations are noted in certain spectra. Isomeric nitrobenzenes are generally more readily differentiated by negative-ion than positive-ion mass spectrometry.

Protective Role of Smooth Lipopolysaccharide in the Serum Bactericidal Reaction

Abstract: The mechanism by which smooth lipopolysaccharide (LPS) protects Salmonella typhimurium C5 from the lethal action of specific antibody and complement has been investigated. Tris(hydroxymethyl)aminomethane (Tris) and ethylenediaminetetraacetate (EDTA), which sensitize S. typhimurium C5 to the bactericidal action of immune serum, were shown to cause appreciable structural modification of the smooth LPS associated with these cells. Mg2+ was shown to reverse the sensitization of C5 by Tris, but this divalent cation was unable to reverse the sensitizing effect of Tris plus EDTA, which, unlike Tris, caused relatively large amounts of O-antigenic components to be released from the C5 cell wall. The possibility that smooth LPS blocks the interaction of activated complement components with receptors on the cell wall is discussed.

The political sciences : general principles of selection in social science and history

Abstract: Social science is a social activity as well as a method of discovery. The researchers’ values and politics colour their work and so do their choices of scientific method. This book is about both – the technical effects of values and the political effects of technique. The author reports what social scientists and historians actually do. He sorts out the scientific from the political content in a wide range of old and new work in history, sociology, political science and economics. The overall work is a detailed political and technical criticism of the ‘scientistic’ programme which would have researchers select for such qualities as objectivity, uniformity, and generality, cumulation and professional unanimity.