Showing papers by "James Cook University published in 1974"
TL;DR: When pieces of the staghorn coral Acropora acuminata are incubated with 14C-urea, the label is incorporated into skeletal carbonate, suggesting urea is not immediately hydrolysed to provide a further source of HCO3-.
Abstract: When pieces of the staghorn coral Acropora acuminata are incubated with 14C-urea, the label is incorporated into skeletal carbonate. Incorporation of this label differs from that of H14CO
3
-
, suggesting urea is not immediately hydrolysed to provide a further source of HCO
3
-
. The effects of certain organic substrates upon calcification suggest the ornithine cycle is involved. Citrulline, an ornithine cycle intermediate, is found in high concentrations in the tissues of hermatypic corals. Urea, allantoins, NH3 and arginine are also present. These compounds are barely detectable in zooxanthellae or an ahermatypic coral. The allantoins may be present as calcium salts. It is suggested that allantoins are the medium by which Ca2+ and CO2 are transported to sites of calcification. Hydrolysis of urea, formed by breakdown of allantoins, yields CO2 and NH3. The NH3 may neutralise protons formed during precipitation of CaCO3 and bring about their removal from sites of calcification. As well as providing urea, the ornithine cycle may also be involved in the removal of NH3 from sites of calcification.
70 citations
TL;DR: The effects of cyclone "Althea" on littoral and sub-littoral biotic communities caused by cyclone ‘althea' which crossed the tropical coast of Queensland on 24 December, 1971, are described in this paper.
63 citations
TL;DR: A sensitivity analysis for a general second-order multiamplifier RC-active network is described and the proposed configurations are shown to be unconditionally insensitive to variations of the GBWP of the amplifiers.
Abstract: A sensitivity analysis for a general second-order multiamplifier RC-active network is described. The conditions for minimized sensitivity to amplifier gain-bandwidth product (GBWP) are established after first formulating the transfer function gain dependence under the assumption of a single-pole representation of the complex amplifier gain. On the basis of a perturbation technique, approximate expressions are presented for the evaluation of the selectivity and frequency sensitivities. By distinguishing a general form of denominator decomposition, the methods available for realization of high Q's with improved sensitivity are explored. Three special cases of the decomposition are identified; two of these, in common with the general case, suggest the use of twin-T null networks with their attendant high passive sensitivities, but the third gives rise to an additional group of circuits 'realizable as double first-order all-pass sections. By comparison with some previous circuits which require matched amplifiers to achieve a low sensitivity, the proposed configurations are shown to be unconditionally insensitive to variations of the GBWP of the amplifiers.
44 citations
TL;DR: In conditions of alternating light and dark, juvenile Penaeus merguiensis de Man are more active during the dark phase and there is an irregular short-term rhythm, suggested that this allows starved prawns to conserve energy.
Abstract: In conditions of alternating light and dark, juvenile Penaeus merguiensis de Man are more active during the dark phase. The rhythm persists in continuous dim red light, but not in continuous bright white light. The period of circadian rhythm shown in continuous dim red light varies between individuals from 22.75 to 26.0 h, with a mean of 23.8 h. The response of prawns to an artificially produced tidal situation is mediated by the presence or absence of water flow. No endogenous component of this tidal rhythm was demonstrated. There is an irregular short-term rhythm (period 2 to 3 h). It is suggested that this allows starved prawns to conserve energy.
42 citations
37 citations
34 citations
TL;DR: A review of the literature on the processing of ilmenite during the last fifty years is given in this paper, with a simplified outline of the major processes currently used for beneficiation and recovery of titanium dioxide and titanium metal from rutile ores.
31 citations
TL;DR: The dry weight yield of plants of Bryophyllum tubiflorum Harvey, a species with Crassulacean acid metabolism characteristics, increased significantly in response to added sodium.
Abstract: The dry weight yield of plants of Bryophyllum tubiflorum Harvey, a species with Crassulacean acid metabolism characteristics, increased significantly (P < 1%) in response to added sodium (0.1 milliequivalents per liter NaCl was supplied to the culture solution initially containing less than 0.08 microequivalents per liter of Na) when grown under short day (8 hours) conditions but not when grown under long day conditions (16 hours).From results of other work with Crassulacean acid metabolism species, it appears likely that under long day conditions, the plants assimilate CO(2) by the C(3) pathway but under short day conditions by the Crassulacean acid metabolism pathway in which metabolic processes common to those operating in the C(1) dicarboxylic pathway are active. It is suggested that sodium is involved in plants assimilating CO(2) with the C(4) and Crassulacean acid metabolism pathways.
27 citations
TL;DR: No one factor capable of causing bull infertility was consistently identified, and the incidence figures for observed conditions of the accessory sex glands were generally comparable to those found in bull populations elsewhere.
Abstract: Summary
The accessory sex glands of 521 slaughtered bulls were examined for lesions; normal anatomical observations were also made.
The average weights and measurements (length and width) of the seminal vesicles and bulbourethral glands of 110 bulls were 34.1 g and 9.1 × 2.5 cm, and 4.6 g and 2.9 × 1.9 cm, respectively. Weights of both glands were correlated to age, but bulbourethral gland weight was more closely correlated to bodyweight than age. The average length and diameter of the ampulla was 11.1 and 1.0 cm, respectively.
Seminal vesiculitis and ampullitis were found in 9.0% and 3.8% of bulls respectively. The incidence of both conditions was highest in old bulls. Mesonephric duct anomalies (observed in 1.7% of bulls) and other congenital and inflammatory lesions of the accessory sex glands were also recorded.
Macroscopically normal accessory sex glands of 86 bulls were studied histologically and a high percentage of all glands showed inflammatory changes.
Attempts to isolate viral agents, Mycoplasma, and Chlamydia from accessory sex glands were unsuccessful. Corynebacterium pyogenes was isolated from two cases of seminal vesiculitis. IBR-IPV virus, Campylobacter fetus subsp. venerealis and Tritrichomonas foetus were frequently isolated from the prepuce of bulls, many of which also had positive serological titres to Leptospira pomona and Leptospira hardjo.
No one factor capable of causing bull infertility was consistently identified, and the incidence figures for observed conditions of the accessory sex glands were generally comparable to those found in bull populations elsewhere.
24 citations
TL;DR: The water turnover of wild brush-tailed possums and plain rockwallabies living in the same environment were determined at intervals throughout 2 years and lactating females had an increased water turnover and higher tritiated water space than non-lactating animals.
19 citations
TL;DR: The products of action of a purified, extracellular endo-dextranase D1, isolated from a new species of Pseudomonas, on pure isomaltose oligosaccharides have been investigated, and a model is postulated for the enzyme active-site, based on substrate specificity.
TL;DR: The protegulum of acrothelid inarticulate brachiopods is characterised by slender, elongate, hilaterally arranged spines which are interpreted as adaptations to facilitate settlement on a soft substrate.
Abstract: The protegulum of acrothelid inarticulate brachiopods is characterised by slender elongate, hilaterally arranged spines which are interpreted as adaptations to facilitate settlement on a soft substrate They provide a mechanism for positioning the gape clear of the substrate and a means of shell eversion to permit recovery from an overturned position Holoperipheral growth and attainment of a low subconical form by the pedicle valve during later growth stages provide different strategies for solving these problems, and the protegular spines become non-functional and largely worn away The structures arc illustrated in a species of Orbithele from the Upper Cambrian of Australia
01 Dec 1974
TL;DR: In this article, Clausen et al. discuss the acquisition of social structure and the socialisation of competence in the context of professional socialisation, and present a study of teachers in Ghana.
Abstract: Anderson. D. and Western J. 1967 ’Notes on a study of professional socialisation’. Australian and New Zealand Journal of Sociology, 3 (1): 67-71. Bittner. E. 1964 ’The concept of organisation’. Social Research, 31: 255. Cicourel. A. 1970 ’The acquisition of social structure’. In J. Douglas (ed.), Understanding Everyday Life. London: Routledge and Kegan Paul. Hymes. D. 1972 ’On communicative competence’. In J. B. Pride and J. Holmes (eds.), Sociolinguistics. Penguin Books. Inkeles. A. 1966 ’Social structure and the socialisation of competence’. Harvard Education Review, 36 (Summer): 265-283. Smith, M. B. 1965 ’Socialisation for competence’. Items, 19: 1723. 1967 ’Explorations in competence — a study of Peace Corps teachers in Ghana’. American Psychologist, 21 (6): 555-66. 1968 ’Competence and socialisation’. In J. A. Clausen (ed.), Socialisation and Society. Boston: Little Brown and Co. White. R. W. 1959 ’Motivation reconsidered — the concept of competence’. Psychological Review, 66:297-333. 1960 ’Competence and the psychosexual stages of development’. In M. Jones (ed.), Nebraska Symposium on Motivation. University of Nebraska Press.
01 Jan 1974
TL;DR: The search for the origins and early mechanisms of immunocompetence among the invertebrates is now well underway and tissue transplantation is recognized as a sensitive and perhaps universally applicable tool for investigation of immunoresponsiveness.
Abstract: The search for the origins and early mechanisms of immunocompetence among the invertebrates is now well underway. Tissue transplantation is recognized as a sensitive and perhaps universally applicable tool for investigation of immunoresponsiveness. Indeed, only orthotopic tissue transplantation may allow meaningful comparisons of reactivity to potentially immunogenic cells among phylogenetically diverse animals. This is because responses to xenogeneic or exotic macromolecules may be limited by the enzymes available to a species rather than by immunologic potential as such. Moreover, endotoxins inherent in many microbial antigen preparations may have effects ranging from stimulating to fatal, depending on the recipient species. A purified protein such as bovine serum albumin is an excellent, satisfactory, or poor immunogen depending on whether the recipient is a rabbit, goldfish, or mouse, respectively (Vredevoe, 1964, Trump, 1970). Thus the choice of test immunogen rather than the innate immunologic capacity of the recipient may be decisive and thus, results can be misleading.
TL;DR: The principles involved in selecting the binary patterns to control the gain of the modulator and as examples a delta modulation system and a pulse-code modulation system with companding ratios of 60 dB are discussed.
Abstract: This paper deals with the requirements for the design of digital companding techniques in either delta or pulse-code modulation. Both delta and pulse-code modulation convert analogue signals into binary signals and in both these systems the dynamic range is normally small. By the use of companding, the dynamic range can be extended. Since both delta and pulse-code modulation are digital methods, they are well suited to the use of digital companding techniques. The binary transmitted signal normally contains a measure of the system performance. By observing certain patterns in this binary signal and using the occurrence or nonoccurrence of these patterns to change the gain of the modulator and demodulator, syllabic companding can be obtained. The selection of the binary pattern and the rate of change of gain of the modulator and demodulator, determines both the point at which the companding operates and the attack and decay times. The ratio of the largest to the smallest value of the gain determines the dynamic range. By the use of digital circuitry, the gain can be controlled with sufficient accuracy over a large dynamic range. The paper deals with the principles involved in selecting the binary patterns to control the gain of the modulator and as examples a delta modulation system and a pulse-code modulation system with companding ratios of 60 dB are discussed.
TL;DR: Examination of the ring-like annuli, situated within the surface walls of the epidermis of Halophila ovalis, revealed that both the annulus, and a site beneath it on the inside of the exterior epidermal wall reacted strongly to silver nitrate.
TL;DR: Hilsdorf developed an ingenious approach to the end effects problem using brush platens as mentioned in this paper, which has considerable potential for use with other materials and other types of loading, but the single disadvantage is the amount of time needed for their construction.
Abstract: A long-standing and universal recognition exists about the influence exerted on the behavior of rock in laboratory compression tests by the nature of the specimen-platen contact. Further, the degree of end restraint has been shown to influence the strength, mode of failure, and shape of the stress-strain curve obtained in laboratory compression tests on rocks. A practicable method of overcoming the end effects problem is needed. Hilsdorf developed an ingenious approach to the end effects problem using “brush platens.” Details of a set of brush platens made for uniaxial compression tests and results of the testing are presented. This approach has considerable potential for use with other materials and other types of loading. The single disadvantage to brush platens is the amount of time needed for their construction.
TL;DR: In this article, the frequency-sensitivity problem associated with some types of very-low-frequency oscillators is examined and an insensitive structure is presented, and the frequency sensitivity problem is analyzed.
Abstract: The frequency-sensitivity problem associated with some types of very-low-frequency oscillators is examined and an insensitive structure is presented.
TL;DR: In this article, the authors derived long term operating tolerances for a quadrupole mass filter driven by a rectangularly periodic r.f. waveform, for operation at half peak height resolutions of about 400 with a transmission stability of about 2%.
TL;DR: In this paper, it was shown that the harmonic composition of the voltage waveform applied to the electrodes of a quadrupole mass filter is analyzed with a view to assessing its affect on device performance.
TL;DR: In this paper, the deformational response to load is determined in shale rock samples of different sizes and shapes, and defects such as cracks, pores and inclusions tend to control the anisotropic characteristics of the material.
TL;DR: In this paper, the MgCO3 content in miliolacen foraminifera is not a reliable tool, for determining palaeotemperature, or palaeodepth, nor is it an aid to classification.
TL;DR: Armstrong and Lindoy as mentioned in this paper reported nickel complexes of a new series of macrocyclic quadridentate ligands derived from salicylaldehyde which contain both imine-nitrogen and ether-oxygen donor atoms.
TL;DR: A preliminary study of the action of enzymes from CS and CP isolated on hemicellulose is reported, and the CP 2 -culture isolate was selected for the study of conditions for the optimal production of extra-cellular hemICEllulase(s).
TL;DR: In this article, a block model with blocks of different sizes is tested with all the blocks in place and the deformation of specific blocks are measured under different load paths and the consequent apparent moduli determined.
TL;DR: Using truncated Hill determinant analysis it is verified that for a quadrupole filter to be mass-selective the voltage applied to the quadrapole electrodes must contain an average component, either externally generated or inherent in the shape of the voltage waveform, or both as mentioned in this paper.