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Showing papers by "Australian National University published in 1977"


Journal ArticleDOI
TL;DR: In this article, standards for reporting C-14 age determinations are discussed, and the statistical uncertainty (plus or minus one standard deviation) expresses counting errors, inaccuracies in voltage, pressure, temperature, dilution, and should include errors in C-13 ratios.
Abstract: Standards for reporting C-14 age determinations are discussed. All dates should be related either directly or indirectly to the NBS oxalic acid standard. Corrections for isotopic fractionation are also desirable. For some materials, particularly marine shell, corrections for reservoir effect are necessary, but these should always be reported separately from the conventional radiocarbon age. The statistical uncertainty (plus or minus one standard deviation) expresses counting errors, inaccuracies in voltage, pressure, temperature, dilution, and should include errors in C-13 ratios. Errors can be significant when isotope ratios are estimated rather than measured directly. The error in the conventional C-14 half life is not included. The article includes tables indicating what data should be reported.

5,579 citations


Journal ArticleDOI
TL;DR: A unified theory is developed that explains the formation of bilayers and vesicles and accounts quantitatively for many of their physical properties: properties including vesicle size distributions and bilayer elasticity emerge from a unified theory that links thermodynamics, interaction free energy, and molecular geometry.

868 citations


Journal ArticleDOI
TL;DR: In this paper, a model is presented to explain the geochemical and mineralogical characteristics of granitoids and their inclusions, and the straight-line variation diagrams of most granitoid suites are explained by progressive separation of residuum (= restite) and melt.

837 citations


Journal ArticleDOI
TL;DR: In this article, it is suggested that the observed variations are a consequence of dynamic partial melting of a homogeneous mantle source region, which may be generated by processes in the mantle during melting.

627 citations


Journal ArticleDOI
TL;DR: Examen des moyens employes par les langues sans adjectif pour exprimer les concepts s'y rapportant and consequences for des "types" semantiques universels as mentioned in this paper.
Abstract: Examen des moyens employes par les langues sans adjectif pour exprimer les concepts s'y rapportant et consequences pour des "types" semantiques universels.

508 citations


Journal ArticleDOI
TL;DR: It is possible to set out an acceptable, noncircular account of the truth conditions of laws and nomological statements if and only if relations among universals that is, among properties and relations, construed realistically are taken as the truth-makers for such statements.
Abstract: This paper is concerned with the question of the truth conditions of nomological statements. My fundamental thesis is that it is possible to set out an acceptable, non Circular account of the truth conditions of laws and nomological statements if and only if relations among universals — that is, among properties and relations, construed realistically — are taken as the truth-makers for such statements. My discussion will be restricted to strictly universal, nonstatistical laws. The reason for this limitation is not that I feel there is anything dubious about the concept of a statistical law, nor that I feel that basic laws cannot be statistical. The reason is methodological. The case of strictly universal, nonstatistical laws would seem to be the simplest case. If the problem of the truth conditions of laws can be solved for this simple subcase, one can then investigate whether the solution can be extended to the more complex cases. I believe that the solution I propose here does have that property, though I shall not pursue that question here.

491 citations


Journal ArticleDOI
TL;DR: In this paper, the authors derive normative tax rules based on the constitutional calculus of the typical voter-taxpayer when he predicts that post-constitutional political processes will be dominated by a budget-maximizing Leviathan-like bureaucracy.

429 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the creep of Solnhofen limestone at temperatures between 600° and 900° C and found that it falls into three different flow regimes: regime 1 with an exponential stress-dependence of strain rate, regime 2 with power-law creep and n ~ 4.7 and regime 3 with n ~ 1.7.

364 citations


Journal ArticleDOI
TL;DR: Improved methods for the activation and assay of d -ribulose-1,5-bisphosphate carboxylase and oxygenase are described and the use of a “CO 2 -free” oxygenase reaction mixture is emphasized along with the difficulties arising from the inevitable carryover of CO 2 into the reaction mixture with the activated enzyme.

333 citations


Journal ArticleDOI
07 Jul 1977-Nature
TL;DR: The action of these compounds as GABA agonists provides indirect evidence that GABA interacts with bicuculline-sensitive postsynaptic receptors in the cat spinal cord in a partially extended and almost planar conformation.
Abstract: COMPOUNDS which mimic the activity of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) on postsynaptic receptors are of particular pharmacological interest as possible therapeutic agents in human neurological disorders and as molecular probes with which to study different types of GABA receptors. The GABA molecule has considerable flexibility with free rotation around all three carbon–carbon bonds as indicated in Fig. 1. This conformational mobility is reduced in GABA analogues such as trans-4-aminocrotonic acid1 and muscimol2, which are potent GABA agonists at bicuculline-sensitive receptors on spinal neurones of the cat. The conformational mobility of such compounds can be reduced still further by incorporating the amino function in a ring structure. This has led to a new class of GABA agonist described here, based on l,2,3,6-tetrahydropyridine-4-carboxylic acid (isoguvacine) and the related bicyclic isoxazole 4,5,6,7-tetra-hydroisoxazolo[5,4-c]pyridin-3-ol (THIP) (Fig. 1). Isoguvacine represents a semi-rigid analogue of trans-4-aminocrotonic acid in a folded conformation. THIP, a folded analogue of muscimol, is even more rigid as the ‘masked’ carboxyl group (the 3-isoxazolo moiety) is fixed in the general plane of the molecule. The action of these compounds as GABA agonists provides indirect evidence that GABA interacts with bicuculline-sensitive postsynaptic receptors in the cat spinal cord in a partially extended and almost planar conformation.

321 citations


Journal ArticleDOI
TL;DR: Based upon soma diameter histograms made for several locations with different eccentricities, ganglion cells were classified into three groups; large (L), medium-sized (M) and small (S) and relative frequencies of the three groups, on average, were 5, 28 and 67%, respectively.

Journal ArticleDOI
TL;DR: In this paper, a set of relative sensitivity values for 31 elements show a factor of 25 between the most sensitive element (Rb) and the least sensitive (Ir), depending on elemental boiling point, ionisation potential, and nuclide mass.

Book ChapterDOI
TL;DR: The present article is aimed at the non-expert, and gives a brief account of the history of the conjecture, its precise formulation, and the partial results obtained so far in support of it.
Abstract: The conjecture of Birch and Swinnerton-Dyer is one of the principal open problems of number theory today. Since it involves exact formulae rather than asymptotic questions, it has been tested numerically more extensively than any other conjecture in the history of number theory, and the numerical results obtained have always been in perfect accord with every aspect of the conjecture. The present article is aimed at the non-expert, and gives a brief account of the history of the conjecture, its precise formulation, and the partial results obtained so far in support of it.


Journal ArticleDOI
TL;DR: It is concluded that the quinones serve to link the various dehydrogenases with the terminal electron transport systems to oxygen and nitrate and that the dehydrogenase possess a degree of selectivity with respect to the qu inone acceptors.

Journal ArticleDOI
TL;DR: The morphological maturation of several varieties of neurons of cortical area 17 have been followed in Golgi Rapid preparations from Macaque monkeys ranging in age from fetal day 127 to maturity and a developmental sequence common to all varieties of neuron is described.
Abstract: The morphological maturation of several varieties of neurons of cortical area 17 have been followed in Golgi Rapid preparations from Macaque monkeys ranging in age from fetal day 127 to maturity. A developmental sequence common to all varieties of neuron is described. Maturation occurs at the same rate at all cortical depths and appears to relate to the size of the neuron rather than to factors such as generation time, arrival at a final laminar position or cell type. The characteristic laminar patterns of cell type distribution and the specific axonal and dendritic arborisations seen in the adult are generated in the earliest stages of growth and do not occur as the result of elimination from a wider, less precise, distribution. During the period from birth to postnatal week 8 a marked increase in the numbers of dendritic spines is seen in all varieties of neuron including those which will be spine-free in the adult. Following this period an equally marked reduction in spine numbers occurs, initially rapid but continuing at a slower rate even nine months postnatally. Possible relationships between these postnatal dendritic spine changes and the extreme sensitivity of the system to visual input during the early postnatal weeks are discussed.

Journal ArticleDOI
TL;DR: Results suggest symptom occurrence was associated with duration of contact with water containing cyanobacteria, and with cyanobacterial cell density, and the current safety threshold for exposure of 20 000 cells per mL may be too high.


Journal ArticleDOI
TL;DR: This paper provides a review of one of the basic problems of systems theory-the general time-invariant optimal control problem involving linear systems and quadratic costs, developed using simple properties of dynamical systems and involves a minimum of 'hard' analysis or algebra.

Journal ArticleDOI
TL;DR: In this article, the dependence of eye design on the environmental light intensity was determined and various strategies for dark-adaptation were considered with the conclusion that neural pooling combined with a widening of the acceptance angle is most effective for coping with reduced intensities.
Abstract: The two fundamental limitations to resolving power of compound eyes are the wave (diffraction) and particle (photon noise) nature of light. By appreciating their interrelationship we gain insight into the design and limitation of eyes. In particular, we determine the dependence of eye design on the environmental light intensity. 1. The limitations to resolving power include: the intensity of light, angular motion, receptor grain, lens-pupil blur, finite diameter of rhabdom, and neural convergence. 2. Only those animals that are active in bright sunlight and normally have low angular velocity, profit by having some region of their eyes near the diffraction limit, i.e.DΔφ ≅ 0.58λ, whereD is the facet diameter,Δφ the interommatidial angle and λ the wavelength in vacuum. If these conditions are not fulfilled, it is better to have a largerDΔφ. 3. The effect of an animal undergoing angular velocityu is equivalent to a reduction in light intensity by the amount exp−1.78(φtΔφ)2, where φt is the amount the animal turns in one integration time. Taking this into account, we present a possible explanation forMusca havingDΔφ about 4.5 times greater than the diffraction limit. 4. Various strategies for dark-adaptation are considered with the conclusion that neural pooling combined with a widening of the acceptance angle is most effective for coping with reduced intensities.

Journal ArticleDOI
TL;DR: Both the selective action of morphine on nociceptive responses and the reversal of this action by intravenous naloxone suggest that the opiate receptor present in the substantia gelatinosa is relevant to analgesia produced by opiates given systemically.
Abstract: 1 In spinal cats anaesthetized with α-chloralose, a study was made of the effects of morphine and naloxone, administered electrophoretically from micropipettes, on the responses of dorsal horn neurones to noxious (raising of skin temperature above 45°C) and innocuous (deflection of hairs) peripheral stimuli. 2 Administered near cell bodies, morphine reduced the nociceptive responses of only 2 of 37 cells. Excitation occurred more commonly than depression and abnormalities in action potentials were commonly observed following ejection of morphine. None of these effects of morphine was antagonized by electrophoretically applied naloxone. 3 Administered in the substantia gelatinosa from one micropipette while recording responses of deeper neurones with a second micropipette, morphine reduced the nociceptive responses of 15 of 19 neurones. Firing in response to deflection of hairs was not reduced by morphine. Depression of nociceptive responses by morphine was long lasting (>20 minutes). Naloxone ejected into the substantia gelatinosa or given intravenously in doses as low as 0.1 mg/kg antagonized the effects of morphine. The effectiveness of this dose of intravenous naloxone suggests that the concentrations of morphine in the substantia gelatinosa which reduced nociceptive responses were not unlike those present after analgesic doses of systemic morphine. Naloxone alone, and excitant and depressant amino acids ejected into the substantia gelatinosa had little effect on cell firing. 4 Both the selective action of morphine on nociceptive responses and the reversal of this action by intravenous naloxone suggest that the opiate receptor present in the substantia gelatinosa is relevant to analgesia produced by opiates given systemically.

Journal ArticleDOI
TL;DR: The maximum center-to-center angular spacing delta phi of photoreceptors tolerated for reconstructing the highest spatial frequency passed by a diffraction-limited pupil of diameter D is delta phI - lambda/D square root 3 when the photoreCEPTors are packed in a hexagonal array, where lambda is the wavelength in vacuum.
Abstract: The maximum center-to-center angular spacing Δϕ of photoreceptors tolerated for reconstructing the highest spatial frequency passed by a diffraction-limited pupil of diameter D is Δϕ = λ/D √3 when the photoreceptors are packed in a hexagonal array, where λ is the wavelength in vacuum. This spacing gives the maximum signal-to-photon noise ratio when the inner segments touch. The mean luminance required for an eye to achieve its highest resolving power is independent of eye size, provided the retina is designed to sample the highest spatial frequency passed by the diffraction-limited optics.

Journal ArticleDOI
TL;DR: Certain molecular packing criteria previously employed in a quantitative analysis of lipid micelles and bilayers are here extended to biological membranes, pointing to a highly complex self-assembly mechanism in which the organization of lipids and proteins is highly coupled.

Journal ArticleDOI
TL;DR: In this article, a suite of Archean sedimentary rocks (2800 million years old) from Kalgoorlie, Western Australia were analyzed for major element and other trace element data.

Journal ArticleDOI
TL;DR: The capacity of the compound eye to perceive its spatial environment is quantified by determining the number of different pictures that can be reconstructed by its array of retinula cells, and an optimum parameterp is found, which is approximately that found by Snyder (1977) for threshold resolution of a sinusoidal grating at the ommatidial sampling frequency.
Abstract: The capacity of the compound eye to perceive its spatial environment is quantified by determining the number of different pictures that can be reconstructed by its array of retinula cells. We can then decide on the best compromise between an animal's capacity for fine detail and contrast sensitivity. The theory accounts for imperfect optics, photon noise, and angular motion limitations to acuity. 1. There is an optimum parameterp = D Δ φ, whereD is the facet diameter andΔ φ is the interommatidial angle, for each mean luminance, angular velocity and mean object contrast. We find that this value ofp is approximately that found by Snyder (1977) for threshold resolution of a sinusoidal grating at the ommatidial sampling frequency. 2. A diffraction limited eye (D Δ φ ≅λ/√¯3) is the optimum design only for those animals that are active in the brightest sunlight, and have a region of their eye that normally experiences low angular velocity, otherwise it is better to have a largerD Δ φ. λ is the wavelength of light in vacuum. 3. The design of the flyMusca is consistent with that of an animal with high angular velocity.


Journal ArticleDOI
TL;DR: In vitro stimulation of primed cells with cells infected with heterologous type A virus of a different subtype specifically selects for the cross-reactive T-cell population in the secondary cytotoxic response of mice with a given strain of type A influenza virus.

Journal ArticleDOI
TL;DR: Cell division in the rat superior cervical and stellate ganglia has been followed from 6 days before birth until 14 days after birth by [3H] thymidine autoradiography, with an increase in the number of neurons in the ganglia when given either over the first four postnatal days while neuronal division was still occurring or from postnatal Days 6–8 after neuronal division had ceased.
Abstract: Cell division in the rat superior cervical and stellate ganglia has been followed from 6 days before birth until 14 days after birth by [3H] thymidine autoradiography. Neuronal division ceased at the postnatal day 4 in superior cervical ganglia and postnatal day 3 in stellate ganglia, whereas division of non-neuronal cells continued throughout the entire period studied. Dividing cells in both ganglia were predominantly neuronal before birth and non-neuronal after the postnatal day 3.

Journal ArticleDOI
TL;DR: In this article, the phase relationships of spinel lherzolite-bearing olivine melilitite from Tasmania were investigated over a P, T range with varying MH-buffered conditions.
Abstract: Near-liquidus phase relationships of a spinel lherzolite-bearing olivine melilitite from Tasmania were investigated over a P, T range with varying $${\text{x}}_{{\text{H}}_{\text{2}} {\text{O}}} $$ , $${\text{x}}_{{\text{CO}}_{\text{2}} } $$ , and $${\text{f}}_{{\text{O}}_{\text{2}} } $$ . At 30 kb under MH-buffered conditions, systematic changes of liquidus phases occur with increasing $${\text{x}}_{{\text{CO}}_{\text{2}} } $$ ( $${\text{x}}_{{\text{CO}}_{\text{2}} } $$ = CO2/CO2 +H2O+olivine melilitite). Olivine is the liquidus phase in the presence of H2O alone and is joined by clinopyroxene at low $${\text{x}}_{{\text{CO}}_{\text{2}} } $$ . Increasing $${\text{x}}_{{\text{CO}}_{\text{2}} } $$ eliminates olivine and clinopyroxene becomes the only liquidus phase. Further addition of CO2 brings garnet+orthopyroxene onto the liquidus together with clinopyroxene, which disappears with even higher CO2. The same systematic changes appear to hold at higher and lower pressures also, only that the phase boundaries are shifted to different $${\text{x}}_{{\text{CO}}_{\text{2}} } $$ . The field with olivine- +clinopyroxene becomes stable to higher $${\text{x}}_{{\text{CO}}_{\text{2}} } $$ with lower pressure and approaches most closely the field with garnet+orthopyroxene+clinopyroxene at about 27 kb, 1160 °C, $${\text{x}}_{{\text{CO}}_{\text{2}} } $$ ∼ 0.08 and $${\text{x}}_{{\text{H}}_{\text{2}} {\text{O}}} $$ ∼ 0.2 (i.e., 6–7% CO2+ 7–8% H2O). Olivine does not coexist with garnet+orthopyroxene+clinopyroxene under these MH-buffered conditions. Lower oxygen fugacities do not increase the stability of olivine to higher $${\text{x}}_{{\text{CO}}_{\text{2}} } $$ and do not change the phase relationships and liquidus temperatures drastically. Thus, it is inferred that olivine melilitite 2927 originates as a ∼ 5% melt (inferred from K2 O and P2O5 content) from a pyrolite source at about 27kb, 1160 dg with about 6–7% CO2 and 7–8% H2O dissolved in the melt. The highly undersaturated character of the melt and the inability to find olivine together with garnet and orthopyroxene on the liquidus (in spite of the close approach of the respective liquidus fields) can be explained by reaction relationships of olivine and clinopyroxene with orthopyroxene, garnet and melt in the presence of CO2.

Journal ArticleDOI
TL;DR: The ant community appeared to be stable in the long term, but there was considerable variability in the numbers and species of ants active at any one time, both on a seasonal and diel basis.
Abstract: The activity of five seed-harvesting and ten non-harvesting species of ants was examined over a 2-year period. The ant community appeared to be stable in the long term, but there was considerable variability in the numbers and species of ants active at any one time, both on a seasonal and diel basis. Only four species were active throughout the year, with activity reduced in winter. Two species were consistently nocturnal, nine were mainly diurnal, and the remaining four species switched from diurnal to more nocturnal activity with increasing temperatures. The changes in the diurnal pattern and intensity of foraging activity were shown to be controlled by several climatic and biotic variables. These were classed as either ‘stimulatory-inhibitory’ which determined whether activity would occur or not, or ‘regulatory’, which set the physical limits to activity and controlled foraging intensity. Factors such as forage availability and colony satiation were placed in the first category, and soil temperature, moisture stress and light intensity were placed in the second. There was no simple response to the combination of variables, and individual species responded differently to the various factors. The resulting temporal separation probably reduces competitive interactions between species.