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Showing papers by "University of Adelaide published in 1970"



Journal ArticleDOI
TL;DR: It is suggested that an ‘ accumulator ’ model, in which sampled events may vary in magnitude as well as probability, can be developed to give a good account of much of the available data on psychophysical discrimination.
Abstract: Recent theoretical approaches to the problem of psychophysical discrimination have produced what may be classified as ‘ statistical decision ’ or ‘ data accumulation ’ models. While the former have received much attention their application to judgment and choice meets with some difficulties. Among the latter, the two types which have received most attention are a ‘ runs ’ and a ‘ recruitment ’ model, but neither seems able to account for all of the relevant data. It is suggested instead that an ‘ accumulator ’ model, in which sampled events may vary in magnitude as well as probability, can be developed to give a good account of much of the available data on psychophysical discrimination. Two experiments are reported, in which the subject presses one of two keys as soon as he has decided whether the longer of two simultaneously presented lines is on the left or right. Results are found to be inconsistent with a runs or recruitment process, but to accord well with predictions from the accumulator model. Oth...

368 citations


Journal ArticleDOI
TL;DR: It is concluded that piericidin A separates ubiquinone from the remainder of the electron-transport chain in the presence of substrate, and a scheme is proposed in which ubisemiquinone, complexed to an electron carrier, functions in at least two positions in the electron -transport sequence.
Abstract: 1. The function of ubiquinone in Escherichia coli was studied by using whole cells and membrane preparations of normal E. coli and of a mutant lacking ubiquinone. 2. The mutant lacking ubiquinone, strain AN59 (Ubi−), when grown under aerobic conditions, gave an anaerobic type of growth yield and produced large quantities of lactic acid, indicating that ubiquinone plays a vital role in electron transport. 3. NADH and lactate oxidase activities in membranes from strain AN59 (Ubi−) were greatly impaired and activity was restored by the addition of ubiquinone (Q-1). 4. Comparison of the percentage reduction of flavin, cytochrome b1 and cytochrome a2 in the aerobic steady state in membranes from the normal strain (AN62) and strain AN59 (Ubi−) and the effect of respiratory inhibitors on these percentages in membranes from strain AN62 suggest that ubiquinone functions at more than one site in the electron-transport chain. 5. Membranes from strain AN62, in the absence of substrate, showed an electron-spin-resonance signal attributed to ubisemiquinone. The amount of reduced ubiquinone (50%) found after rapid solvent extraction is consistent with the existence of ubiquinone in membranes as a stabilized ubisemiquinone. 6. The effects of piericidin A on membranes from strain AN62 suggest that this inhibitor acts at the ubiquinone sites: thus inhibition of electron transport is reversed by ubiquinone (Q-1); the aerobic steady-state oxidation–reduction levels of flavins and cytochrome b1 in the presence of the inhibitor are raised to values approximating those found in the membranes of strain AN59 (Ubi−); the inhibitor rapidly eliminates the electron-spin-resonance signal attributed to ubisemiquinone and allows slow oxidation of endogenous ubiquinol in the absence of substrate and prevents reduction of ubiquinone in the presence of substrate. It is concluded that piericidin A separates ubiquinone from the remainder of the electron-transport chain. 7. A scheme is proposed in which ubisemiquinone, complexed to an electron carrier, functions in at least two positions in the electron-transport sequence.

176 citations


Journal ArticleDOI
TL;DR: An account is given of the benthic marine algae (and sea grasses) collected on the 1965 Royal Society Expedition to the Solomon Islands, comprising some 71 species of Chlorophyta, 27 of Phaeophyta), 121 of Rhodophyta and 14 of Cyanophyta.
Abstract: An account is given of the benthic marine algae (and sea grasses) collected on the 1965 Royal Society Expedition to the Solomon Islands. The known algal flora is fairly typical of such a tropical area, comprising some 71 species of Chlorophyta, 27 of Phaeophyta, 121 of Rhodophyta and 14 of Cyanophyta. Pseudobryopsis solomonensis , P. gracilis, Caulerpa spathulata and Cryptonemia ? subdichotoma are newly described. Seven species of sea grasses are also recorded.

172 citations



Journal ArticleDOI
TL;DR: The results of the clinical series and the histologic material support theConservative approach to the treatment of pulpless, incompletely developed teeth because of its simplicity, the lack of surgical trauma, and the improved prognosis afforded by the further root development.

139 citations


Journal ArticleDOI
TL;DR: In this paper, a theory is developed for calculating oscillations of harbours of constant depth and arbitrary shape, based on the solution of a singular integral equation, and numerical results have been calculated for rectangular and complex-shaped harbours.
Abstract: A theory is developed for calculating oscillations of harbours of constant depth and arbitrary shape. This theory is based on the solution of a singular integral equation. Numerical results have been calculated for rectangular harbours so as to check the accuracy of the method. Examples for wave amplification factor and velocity field for both rectangular and actual complex-shaped harbours are given.

119 citations


Journal ArticleDOI
TL;DR: Recent field trials conducted in the Matlab Bazaar area of East Pakistan have indicated that there is a clear correlation between cholera vaccination and infection in any experimental animal.
Abstract: Research in cholera has been greatly hampered by the lack of a clearly correlated model of infection in any experimental animal. The value of various cholera vaccines must, at the moment, be assessed by expensive and prolonged clinical trials in those climatically difficult areas of the world where the disease is endemic. Recent field trials conducted in the Matlab Bazaar area of East Pakistan [1-7] have indicated that there is a clear correlation be-

103 citations


Journal ArticleDOI
01 Jun 1970
TL;DR: The synthesis method is employed for the design of servo-suspensions of the electro-hydraulic type and two alternative arrangements are considered in which the hydraulic actuators and the body support...
Abstract: The synthesis method is employed for the design of servo-suspensions of the electro-hydraulic type. Two alternative arrangements are considered in which the hydraulic actuators and the body support...

99 citations


Journal ArticleDOI
TL;DR: It is proposed that the pH gradient across the plasmalemma is controlled by charge-separating reactions which produce an active H+ efflux, and that Cl− uptake is linked to OH− efflux by ion-exchange reactions.
Abstract: Summary Active chloride uptake by cells of Chara corallina decreases as the pH of the bathing solution is increased, using a range of buffers. Superimposed on this effect, large stimulations of Cl− uptake can be obtained by the addition of imidazole and tris buffers or ammonium sulphate. ‘Stimulated’ or ‘normal’ Cl− influxes respond similarly to the presence of metabolic inhibitors. It is suggested that these effects are not due to changes in photosynthesis or respiration, but reflect the dependence of Cl− transport on the pH gradient across the plasmalemma. Possible ways in which Cl− transport might be linked to H+ or OH− fluxes are discussed. It is proposed that the pH gradient across the plasmalemma is controlled by charge-separating reactions which produce an active H+ efflux, and that Cl− uptake is linked to OH− efflux by ion-exchange reactions. The metabolic implications of this scheme are discussed in detail, with reference to previous work on Characean and other plant cells.

79 citations


Journal ArticleDOI
TL;DR: The concentrations of adenosine triphosphate and phytic acid in testa, embryo plus scutellum, aleurone, and endosperm fractions from grain of Triticum vulgare cv are not consistent with physiological roles previously suggested for phYtic acid.
Abstract: The concentrations of adenosine triphosphate and phytic acid in testa, embryo plus scutellum, aleurone, and endosperm fractions from grain of Triticum vulgare cv. Insignia have been determined during development under both normal conditions and those of water stress. Phytic acid was not detected in the endosperm. In the embryo plus scutellum and aleurone fractions there was a rapid build-up of phytic acid, but the adenosine triphosphate level did not change markedly at this time. These results are not consistent with physiological roles previously suggested for phytic acid other than the role of phytin as a phosphorus and cation store for the germinating seed.

Journal ArticleDOI
TL;DR: A significant linear regression existed between concentration of vitamin B 12 in the liver of a sheep and the logarithm of the concentration in the serum, and there was a linear positive correlation between the rate of depletion of Vitamin B 12 from the liver and the concentration prior to cessation of treatment.
Abstract: 1. Sheep confined topens and given a cobalt-deficient ration which supplied about 30μgCo/d required for maintenance of normal growth rate a Co supplement approaching 40 μg administered per os daily; for maintenance of what appeared, under the conditions of the experiments described, to be the maximum vitamin B12 status of a sheep, namely 3 ng vitamin B12/ml serum and 1.4 μg vitamin B12/g liver tissue, a supplement of between 0.5 and 1.0 mg Co/d per os was necessary.2. For maintenance of normal growth rate the minimum daily requirement for vitamin B12 of sheep given the Co-deficient diet was about 11μg: about 5 μg absorbed from the gut and about 6 μg injected parenterally.3. Extrapolation of the linear regression obtained by plotting the amount of vitamin B12injected/d against concentration of vitamin B12 in the liver tissue of a sheep indicated that to attain a concentration of 1.4 μg vitamin B12/g liver (wet weight) injection of 34 μg vitamin B12/d was necessary.4. Comparison of the relative effects on body-weight of the administration of 100 μg vitamin B12/dper os and 3.12 μg vitamin B12/d by injection to sheep given the Co-deficient diet indicated that the efficiency of absorption of the vitamin from the gut was < 3%.5. Loss of appetite, the first symptom of vitamin B12 deficiency to appear in the sheep, occurred when the concentration of vitamin B12 in the liver was reduced to about 0.1 μg/g wet weight.6. In sheep given a supplement of 1 mg Co/d per os neither production in the rumen nor absorption from the gut but rather capacity for storage limited the concentration of vitamin B12 in the liver.7. Following treatment to restore the vitamin B12 status of a sheep whose stores of the vitamin had been depleted, there was a linear negative correlation between the increase in the concentration of vitamin B12 in the liver and the concentration prior to treatment.8. Following withdrawal of treatment from a sheep whose stores of vitamin B12 were adequate, there was a linear positive correlation between the rate of depletion of vitamin B12 from the liver and the concentration prior to cessation of treatment.9. The concentrations of vitamin B12 in the serums of sheep given the Co-deficient diet, and given a supplement of 1 mg Co/d per os 0.5 h after feeding, remained relatively stable over the period 0–7 h after feeding; maximum concentration occurred 7–8 h after feeding.10. Under the conditions of the experiments described a significant linear regression existed between concentration of vitamin B12 in the liver of a sheep and the logarithm of the concentration in the serum.


Journal ArticleDOI
TL;DR: In the early 1970s, central Australia received some of its heaviest rainfall on record, with total gaugings of 120-350 mm, with some stations receiving overnight falls of over 150 mm.

Journal ArticleDOI
TL;DR: In this paper, an array of 89 aerials were used to test the validity of the usual methods of measuring ionospheric drifts, in which only three aerials are used, and it was shown that the magnitude of the true velocity determined by "full correlation analysis" increases as the size of the aerial triangle increases, and tends to a limit which is the correct value.


01 Jan 1970
TL;DR: In this article, the authors describe the mechanisms related to the extraction, characterization, and significance of soil polysaccharides, and the most successful of which are based on gel filtration and chromatography on charged supports such as cellulose.
Abstract: Publisher Summary Although much is known about the nature and function of many polysaccharides synthesized by individual organisms, there is little information relating to the polysaccharides produced in an environment such as the soil, which in a unique way to bring together a great variety of biological forms. Polysaccharides have been extracted from soils by many different chemical reagents, and recently methods have been devised that enable most of the carbohydrates to be isolated from other soil materials. The extracted polysaccharides show a continuum of molecular sizes and contain a wide range of neutral and charged monosaccharides, amino acids, and other unidentified nitrogenous and acid components. Carbohydrates from different soils are similar in chemical composition suggesting that the microbial population of different soils is qualitatively similar. This chapter describes the mechanisms related to the extraction, characterization, and significance of soil polysaccharides. Many methods have been used to fractionate extracted soil polysaccharides, the most successful of which are based on gel filtration and chromatography on charged supports such as cellulose. The composition of soil polysaccharides suggests that in soils they may carry charged sites and take part in exchange reactions and act as energy sources for heterotrophic organisms. However, the main stimulus for the study of soil polysaccharides has arisen from repeated indications of their favorable influence on soil physical conditions. Much work has been directed toward this aspect, and it has been shown that microbially produced soil polysaccharides are capable of stabilizing soil aggregates against dispersion in water. Methods for the isolation of polysaccharides from other soil materials in good yield are now available and carbohydrate chemists have developed methods for the analysis of extracted polysaccharides.

Journal ArticleDOI
TL;DR: Measurement of ketone bodies by using specific enzymic methods showed that blood of normal sheep and cattle has a high [3-hydroxybutyrate]/[acetoacetate] ratio, in contrast with that of non-ruminants (rats and pigeons).
Abstract: 1. 3-Hydroxybutyrate dehydrogenase (EC 1.1.1.30) activities in sheep kidney cortex, rumen epithelium, skeletal muscle, brain, heart and liver were 177, 41, 38, 33, 27 and 17μmol/h per g of tissue respectively, and in rat liver and kidney cortex the values were 1150 and 170 respectively. 2. In sheep liver and kidney cortex the 3-hydroxybutyrate dehydrogenase was located predominantly in the cytosol fractions. In contrast, the enzyme was found in the mitochondria in rat liver and kidney cortex. 3. Laurate, myristate, palmitate and stearate were not oxidized by sheep liver mitochondria, whereas the l-carnitine esters were oxidized at appreciable rates. The free acids were readily oxidized by rat liver mitochondria. 4. During oxidation of palmitoyl-l-carnitine by sheep liver mitochondria, acetoacetate production accounted for 63% of the oxygen uptake. No 3-hydroxybutyrate was formed, even after 10min anaerobic incubation, except when sheep liver cytosol was added. With rat liver mitochondria, half of the preformed acetoacetate was converted into 3-hydroxybutyrate after anaerobic incubation. 5. Measurement of ketone bodies by using specific enzymic methods (Williamson, Mellanby & Krebs, 1962) showed that blood of normal sheep and cattle has a high [3-hydroxybutyrate]/[acetoacetate] ratio, in contrast with that of non-ruminants (rats and pigeons). This ratio in the blood of lambs was similar to that of non-ruminants. The ratio in sheep blood decreased on starvation and rose again on re-feeding. 6. The physiological implications of the low activity of 3-hydroxybutyrate dehydrogenase in sheep liver and the fact that it is found in the cytoplasm in sheep liver and kidney cortex are discussed.

Journal ArticleDOI
TL;DR: The dansyl-Edman procedure showed that plastocyanin has only the one NH2-terminal sequence, Leu-Glx-Val-Leu, and reduction and carboxymethylation of the apoprotein gave a homogeneous product, as judged by acrylamide gel electrophoresis and Sephadex gel chromatography.

Journal ArticleDOI
TL;DR: An early intermediate of sulphide oxidation in cell-free extracts of Thiobacillus concretivorus is bound to a membrane fraction, and its properties suggest that it is in a linear polymeric form rather than the more stable S 8 ring structure.

Journal ArticleDOI
TL;DR: In this paper, the uptake of phosphate from stirred solution by roots was not affected by root hairs, but root hairs appreciably increased the uptake from a clay soil, and root hairs were found to increase the uptake rate of phosphate.
Abstract: The uptake of phosphate from stirred solution by roots was not affected by root hairs. In contrast to this, root hairs appreciably increased the uptake of phosphate from a clay soil.

Journal ArticleDOI
TL;DR: The importance of carnitine acetyltransferase in sheep liver and its role in relieving ;acetyl pressure' on the CoA system is discussed.
Abstract: 1. Carnitine acetyltransferase (EC 2.3.1.7) activity in sheep liver mitochondria was 76nmol/min per mg of protein, in contrast with 1.7 for rat liver mitochondria. The activity in bovine liver mitochondria was comparable with that of sheep liver mitochondria. Carnitine palmitoyltransferase activity was the same in both sheep and rat liver mitochondria. 2. The [free carnitine]/[acetylcarnitine] ratio in sheep liver ranged from 6:1 for animals fed ad libitum on lucerne to approx. 1:1 for animals grazed on open pastures. This change in ratio appeared to reflect the ratio of propionic acid to acetic acid produced in the rumen of the sheep under the two dietary conditions. 3. In sheep starved for 7 days the [free carnitine]/[acetylcarnitine] ratio in the liver was 0.46:1. The increase in acetylcarnitine on starvation was not at the expense of free carnitine, as the amounts of free carnitine and total acid-soluble carnitine rose approximately fivefold on starvation. An even more dramatic increase in total acid-soluble carnitine of the liver was seen in an alloxan-diabetic sheep. 4. The [free CoA]/[acetyl-CoA] ratio in the liver ranged from 1:1 in the sheep fed on lucerne to 0.34:1 for animals starved for 7 days. 5. The importance of carnitine acetyltransferase in sheep liver and its role in relieving `acetyl pressure' on the CoA system is discussed.

Journal ArticleDOI
TL;DR: In this paper, the excess Gibbs energy per unit volume was found to be a symmetrical function of the volume fraction for the benzene + alkane systems, which is the case for all the systems.


Journal ArticleDOI
TL;DR: The discovery that the “phytic acid” from chicken blood was myo-inositol 1,3,4,5,6 pentaphosphate 11, and not a hexaphosphates has provided a cornerstone for the establishment of the structural relationships among the myo, inositol pentaph phosphates (I-VI).
Abstract: myo-Inositol can give rise to six different penta-0-dihydrogen phosphates (I-VI) (FIGURE 1) ; two of these have a plane of symmetry (I1 and V) and are meso compounds. The remaining four pentaphosphates are optically active and exist as two racemic pairs (I and 111, IV and VI). In symmetrical environments the enantiomorphs of each racemic pair are indistinguishable and the situation simplifies to the examination of four positional isomers. The electrophoretic separation2 of these four isomers formed the basis for a tentative assignment of structures. myo-Inositol pentaphosphate fractions have been isolated from the chemicaP.4 and e n z y m i ~ ~ , ~ hydrolysis of cereal grain phytic acid, which is now known5 to have the Anderson hexaorthophosphate structure VII. The recog&ion5 that the “phytic acid” from chicken blood was myo-inositol 1,3,4,5,6 pentaphosphate 11, and not a hexaphosphate, has provided a cornerstone for the establishment of the structural relationships among the myo-inositol pentaphosphates (I-VI) . The preparation and structural assignments of the remaining isomers has been achieved using methods and techniques given in the references .z * 9 5,

Journal ArticleDOI
01 Jan 1970-Nature
TL;DR: The oldest fossils are from Cretaceous beds along the eastern edge of the Rocky Mountains from Alberta to Texas, and the present bio-geographical distribution of marsupials is set out.
Abstract: RECENT reviews1–3 have set out the facts of the present bio-geographical distribution of marsupials and of the known fossil record. The oldest fossils are from Cretaceous beds along the eastern edge of the Rocky Mountains from Alberta to Texas1,4–6.

Journal ArticleDOI
TL;DR: An alkali-basalt from Hualalai, Hawaii, previously examined by Yoder and Tilley (1962) has been crystallised under controlled PO2 at 2 kb total pressure as mentioned in this paper.

Journal ArticleDOI
01 Jan 1970-Lithos
TL;DR: In this paper, a scheme to standardise the terminology used to describe the textures of granulite facies rocks is outlined which, as far as possible, uses descriptive rather than genetic words.

Journal ArticleDOI
TL;DR: Ethiopia has achieved the 50% reduction of the incidence rate of HIV/AIDS based on the Millennium Development Goals (MDGs) target, however, the decline in HIV/ AIDS mortality rate has been comparatively slow.
Abstract: Background: The burden of HIV/AIDS in Ethiopia has not been comprehensively assessed over the last two decades. In this study, we used the 2016 Global Burden of Diseases, Injuries and Risk factors (GBD) data to analyze the incidence, prevalence, mortality and Disability-adjusted Life Years Lost (DALY) rates of Human Immunodeficiency Virus / Acquired Immune Deficiency Syndrome (HIV/AIDS) in Ethiopia over the last 26 years. Methods: The GBD 2016 used a wide range of data source for Ethiopia such as verbal autopsy (VA), surveys, reports of the Federal Ministry of Health and the United Nations (UN) and published scientific articles. The modified United Nations Programme on HIV/AIDS (UNAIDS) Spectrum model was used to estimate the incidence and mortality rates for HIV/AIDS. Results: In 2016, an estimated 36,990 new HIV infections (95% uncertainty interval [UI]: 8775-80262), 670,906 prevalent HIV cases (95% UI: 568,268-798,970) and 19,999 HIV deaths (95% UI: 16426-24412) occurred in Ethiopia. The HIV/AIDS incidence rate peaked in 1995 and declined by 6.3% annually for both sexes with a total reduction of 77% between 1990 and 2016. The annualized HIV/AIDS mortality rate reduction during 1990 to 2016 for both sexes was 0.4%. Conclusions: Ethiopia has achieved the 50% reduction of the incidence rate of HIV/AIDS based on the Millennium Development Goals (MDGs) target. However, the decline in HIV/AIDS mortality rate has been comparatively slow. The country should strengthen the HIV/AIDS detection and treatment programs at community level to achieve its targets during the Sustainable Development Program (SDGs)-era.

Journal ArticleDOI
F Ledwith1
TL;DR: An investigation was made of the effects on choice reaction time and movement time of hypoxia (oxygen deprivation) induced by a reduction in total air pressure inside a decompression chamber, finding that from gTOund level to 7,000 ft or 10,000ft there was a significant increase in reaction timeand a significant decrease in movement time.
Abstract: An investigation was made of the effects on choice reaction time and movement time of hypoxia (oxygen deprivation) induced by a reduction in total air pressure inside a decompression chamber. The subjects were adult humans who were given no pre training on the task used, were tested once at a pressure level equivalent to some altitude between ground level and 15,000 ft, and were given no information on the altitude attained. A variety of tasks were used with simple and complex spatial and code relationships between stimulus and response. In three experiments on 92 subjects in all the most consistent finding was that from gTOund level to 7,000 ft or 10,000 ft there was a significant increase in reaction time and a significant decrease in movement time. Above 10,000 ft the results were less consistent, reaction time showing further increase or a decrease to that found at ground level and movement times varying in the opposite direction to these changes. It was suggested that in young adult subjects and in t...