Showing papers by "University of Adelaide published in 1977"

Asymptotic similarity of turbulence structures in smooth- and rough-walled pipes

Abstract: Work recently reported by the authors (Perry & Abell 1975) on smooth-walled pipe flow showed support for the Townsend (1976) structural similarity principle as regards viscosity not being directly relevant in controlling the mean relative motions and the energy-containing turbulent motions. The work also supported a universal spectral behaviour in the wall region of the flow. In many hypotheses for rough-walled pipe flow, surface roughness, like viscosity, enters the problem only via external boundary conditions. Data obtained in a rough pipe are reported here and on first appearance the results seem to contradict the Townsend hypothesis and to threaten the very foundation upon which many similarity laws for rough-walled flows are based. However, on closer examination of the spectrum scaling of smooth-walled pipe flow the low and high wavenumber energy not necessarily associated with the universal similarity range can be accounted for. The broad-band longitudinal turbulence results for a rough-walled pipe can then be predicted from the smooth-wall scaling. The conclusion is that, despite the apparent anomalies, the turbulence structure in a rough pipe appears to follow the same scaling laws as for a smooth pipe, given a sufficient length of flow development in both cases. The deduced functional forms are consistent with Townsend's (1976) attached-eddy hypothesis.

Transfer of virulence in vivo and in vitro in Agrobacterium.

Abstract: TRANSFER of virulence from a pathogenic to a non-pathogenic strain of Agrobacterium has been reported to occur in vivo1,2 and is due to the transfer of a plasmid which codes for virulence3,4. In the experimental conditions described, virulence transfer can be detected only after several weeks. The reason for this delay is not clear. The most likely explanations are (1) that infrequent transfer occurs long before it can be detected, detection being dependent on a subsequent increase in the ratio of converted to unconverted recipients or (2) that conditions suitable for virulence transfer occur only after donor and recipient have been in contact for several weeks. The main difficulty in distinguishing between these two alternatives is technical. When pathogenicity testing is used to detect virulence transfer, low frequency transfer is impossible to detect unless thousands of inoculations are made at each assessment. It is known, however, that the virulence plasmid codes for characters other than virulence5–7. One of these is utilisation of octopine and, as Kerr8 has pointed out, this could be used instead of pathogenicity testing to detect plasmid transfer. This communication describes both in vivo and in vitro transfer of virulence using octopine utilisation to detect plasmid transfer.

Inhibition of proline oxidation by water stress.

Abstract: The conversion of proline to glutamic acid and hence to other soluble compounds (proline oxidation) proceeds readily in turgid barley (Hordeum vulgare) leaves and is stimulated by higher concentrations of proline. This suggests that proline oxidation could function as a control mechanism for maintaining low cellular levels of proline in turgid tissue. In water-stressed tissue, however, proline oxidation is reduced to negligible rates. These results are consistent with the idea that proline accumulation results from inactivation by water stress of normal control mechanisms. It seems likely that inhibition of proline oxidation is necessary in maintaining the high levels of proline found in stressed barley leaves.

Energy requirement for symbiotic nitrogen fixation

Abstract: Comparing the energy required by legumes for symbiotic nitrogen fixation with that of assimilation of nitrate, Gibson concluded the costs to be about the same. About 15% of net photosynthetic production by the plant may be used in meeting its nitrogen requirements. If energy for the fixation of nitrogen symbiotically and that for the assimilation of NH4+ or NO3- from the soil solution are both provided by the chemical products of photosynthesis, then the CO2 respired in supplying that energy must contribute to the total efflux of CO2 from the plant in the dark. McCree and Thornley have discussed methods of partitioning the dark CO2 efflux into a growth (synthesis) and a maintenance component. Both nitrogen fixation and nitrogen assimilation can be expected to contribute to the CO2 flux associated with synthesis. If Gibson is correct, nodulated plants using only symbiotically fixed nitrogen should have the same growth coefficient as non-nodulated plants supplied with exogenous mineral nitrogen when grown in the same conditions. I have examined this hypothesis using a modification of the method used by McCree with Trifolium subterraneum L. cultivar Woogenellup as test material.

Agrocin 84 is a 6-N-phosphoramidate of an adenine nucleotide analogue.

Abstract: WE wish to draw attention to the natural occurrence of an extraordinarily selective antibiotic, agrocin 84, which is a ‘fraudulent’ member (structure I) of the hitherto unreported 6-N-phosphoramidate series of adenine nucleotides (structure II), of which 6-N-AMP (II, R=H) is the first member.

Intra-uterine healing of fetal rat oral mucosal, skin and cartilage wounds.

Abstract: . Orofacial wounds, including rupture of the palate, were surgically created in utero on 19½ day Sprague Dawley rat fetuses. Six hours prior to sacrifice 0.1 mgm/100 gm maternal body weight of colchicine was injected subcutaneously. Five fetuses in each group of operated and unoperated controls were sacrificed at 0, 24, 48 and 72 h postoperatively. Serial histological sections in the frontal plane were stained with hemotoxylin and eosin and modified Mallory's. Rapid and complete epithelialization of oral and skin wounds was observed within the 72 h period. There was a complete lack of inflammatory response, scab formation and involvement of nasal epithelium in healing. Nasal cartilage wounds rapidly rounded off and the perichondrium reformed without evidence of callus formation. These findings are discussed in regard to the etiology of some congenital defects and the prospect of fetal surgical correction of orofacial deformity.

The comparative ecology of ten species of honeyeaters in South Australia

Abstract: We describe the habitats and feeding sites used by ten species of honeyeaters in the Mount Lofty Ranges near Adelaide, South Australia.Five of the species have relatively short beaks and feed chiefly on insects gleaned from leaves and bark or captured in the air. They also visit the flowers of Eucalyptus and occasionally of other plants. Species in the same genus occupy different habitats. The five longer-beaked species feed more often onflowers of a wider variety including Eucalyptus, tubular flowers of the heaths and the inflorescences of bottle-brushes. They also feed on insects, most of which they capture in the air. Most of these species overlap broadly in habitat and thus form a guild of species which are very similar in their overall ecology.

Determination of the sequence homology between the four BNA species of cucumber mosaic virus by hybridization analysis with complementary DNA

Abstract: The method of Taylor etal., (11) has been used to transcribe complementary DNA probes from the four major RNA species of cucumber mosaic virus (RNAs 1 - 4 in order of decreasing molecular weight). Analysis of the kinetics of hybridization of these probes in homologous and heterologous complementary DNA-RNA hybridization reactions has shown that the sequence of the smallest RNA (RNA 4), which contains the coat protein gene, is present within RNA 3. RNAs 1 and 2 are unique RNA molecules while each has a region of approximately 300 nucleotides in common with RNA 4.

Tectonic relationships between the Proterozoic Gawler and Willyama orogenic domains, Australia

Abstract: Stratotectonic and morphotectonic data from the two principal exposed domains (pre-Adelaidean rocks) of the Gawler sub-province are used to characterize the Proterozoic Olarian orogeny and to distinguish its effects from those of the later Phanerozoic Delamerian orogeny. The principal metasedimentary sequences in the Gawler domain and in the Willama domain are inferred to have been deposited in a single broad zone of early Proterozoic shallow-water sedimentation on older (presumed Archaean) continental crust. The sequence becomes more pelitic upwards and may be interpreted as a transgressive sequence with more distal facies to the east. Three main phases of deformation are recognized, and each phase has similar characteristics and age in both domains. D1 2nd D2 can be dated between 1850 and 1650 Ma, while D3 appears to be about 1650-1540 Ma. In high grade rocks, D1 gave rise to a layer-parallel schistosity, while D2 is characterized by tight folds with a high-grade axial-plane schistosity. The whole subprovince was characterized by high geothermal gradients so that medium- to highgrade metamorphism affected the lower parts of the succession before and during the D1 and D2 deformation episodes. No distinct tectonic zones can be recognized but large-scale stratigraphic inversions (i.e. nappe tectonics) during D1 have been recognized only in the east of the Willyama domain. The higher parts of the stratigraphic succession are generally less deformed and exhibit only low-grade metamorphism. D3 produced relatively open, upright macroscopic folds and was characteristically associated with retrogression, but was demonstrably of pre-Adelaidea n age. The Gawler domain exhibits D3 structures although it lies in the platform west of the Adelaide Geosyncline and was not affected by deformation during Adelaidean sedimentation or by the subsequent Delamerian orogeny. A network of retrograde shear zones is the principal expression of post-Olarian deformation in the Willyama domain which forms part of the basement to the Adelaide Geosyncline. The trends of D2 and D3 folding in the two domains are similar and it is shown therefore that no large-scale rotations of one domain relative to the other has been produced by the Delamerian orogeny. Large-scale translations on discrete faults or on broad zones of simple shear in the basement are not easily ruled out, but if they exist, are probably largely of pre-Adelaidea n age. However, a significant relationship between Olarian structures and variable Adelaidean fold trends has been deduced. The Olarian orogeny may have occurred in close proximity to a continental margin to the east and may thus be related to subduction processes. It differs from linear gneissic belts in Phanerozoic orogenies since it occurs in a more stable stratotectonic environment and over a wider area.

The optical properties of amorphous and crystalline silicon

Abstract: The optical constants n and k of amorphous and crystalline films of silicon have been found from measurements of reflectance and transmittance at normal incidence over the wavelength range from 2500 to 500 nm, and extended to 300 nm by the method of measuring reflectances from the specimen itself and after depositing on it a thin layer of Ta2O5. This latter method has also been made of the effects of annealing on amorphous films. The measurements on single-crystal silicon have been compared with the results of others obtained by Kramers-Kronig analysis.

Pyrophosphate Inhibition of Carbon Dioxide Fixation in Isolated Pea Chloroplasts by Uptake in Exchange for Endogenous Adenine Nucleotides

Abstract: Carbon dioxide-dependent O(2) evolution by isolated pea (Pisum sativum) chloroplasts was inhibited by inorganic pyrophosphate (PPi). Oxygen evolution was also inhibited by high concentrations of orthophosphate (Pi) and the inhibition was relieved by 3-phosphoglycerate. In contrast, the inhibition by PPi was not relieved by 3-phosphoglycerate, indicating that hydrolysis of PPi and accumulation of inhibitory concentrations of Pi were not occurring. In agreement with this suggestion, the percentage of (14)C-labeled products diffusing out of the chloroplasts was increased by Pi but not by PPi. The inhibition of O(2) evolution by PPi was reversed by ATP. The concentration of PPi required for 50% inhibition was 1.2 to 1.4 mm and the subsequent stimulation by ATP was half-maximal at 16 to 25 mum. Carbon dioxide-dependent O(2) evolution by spinach chloroplasts, or chloroplasts isolated from older pea plants, was not significantly inhibited by PPi.Chloroplasts were preloaded with (14)C-ATP and release of the labeled nucleotides was measured to assess the activity of adenine nucleotide transport across the inner chloroplast envelope membrane. A rapid exchange was promoted by the addition of exogenous ATP. Addition of PPi also resulted in a release of endogenous nucleotides. We suggest that PPi inhibits CO(2) fixation by entering the chloroplast in exchange for endogenous adenine nucleotides via the transporter on the inner envelope membrane. The subsequent depletion of the internal adenine nucleotide pool would result in decreased CO(2) fixation due to insufficient ATP. Addition of ATP to PPi-inhibited chloroplasts apparently results in uptake of catalytic amounts of ATP and restoration of the internal adenine nucleotide pool thus relieving the inhibition of CO(2) fixation.

Development of a layered crenulation cleavage in mica schists of the Kanmantoo Group near Macclesfield, South Australia

Abstract: Kanmantoo Group metasedimentary rocks are folded by a large, dextral, second-generation fold near Macclesfield, South Australia. In the hinge regions of this fold, pelitic schists are crenulated, which gives rise to a variably developed, layered, axial-plane crenulation cleavage. The layered cleavage is produced by different microstructural, mineralogical, and chemical changes on alternate limbs of asymmetric crenulations. The long limbs (mica or M domains) become enriched in muscovite at the expense of biotite, quartz, and feldspar with a consequent large increase of Al 2 O 3 and a smaller increase in K 2 O at the expense of SiO 2 , MgO, and FeO + Fe 2 O 3 . The compositional changes in the short limbs (quartz-feldspar or QF domains) are somewhat complementary, but comparison with uncrenulated rock within 20 mm of these crenulations shows that the layering development involves a bulk chemical change, primarily a depletion in MgO and FeO + Fe 2 O 3 . All mineral grains are finer and less equidimensional in M domains and coarser and more equidimensional in QF domains than in the equivalent uncrenulated rock. In addition, very little evidence of intracrystalline deformation, recovery, or partial re-crystallization was found in a wide range of variably intensely crenulated rocks. The crenulation cleavage probably developed by a combination of (1) rotation of existing grains accompanied by modification of their shape and size by diffusive processes, (2) migration of material, on the scale of grains and domains, controlled by the deformation path and microstructural anisotropies, and (3) nucleation and growth of grains with an orientation and shape compatible with the strain history in their vicinity during nucleation and growth. It is shown that a pressure solution mechanism driven solely by differences in stress magnitude will not explain the range of micro-structural and mineralogical changes. More important controls on diffusive mass transfer are likely to be available from the chemical reactions, strain history, volume changes, and microstructural anisotropies.

A Political Sociology of Home Ownership in Australia

Abstract: ment (MacMurray, 1971 ), and inter-regional movement of households (Weinstein, 1975a, 1975b), there is no body of literature which constitutes anything approaching a systematic sociology of home-ownership. Perhaps more remarkable, in view of the great importance of home-ownership in Australian society, is the absence of any in-depth sociological studies of home-ownership in Australia. One of the most pervasive myths which has become almost universally accepted in Australia is the idea that homeownership is inherently the most superior form of tenure; a belief which finds expression in the elevation of home-ownership into ’The Great Australian Dream’. This, together with political beliefs about ’a property-owning democracy’, combine to produce what is undoubtedly the most powerful ideology in Australian social and political life.

Genetic distance between the Australian Merino and the Poll Dorset Sheep

Abstract: Merinos (189) and Poll Dorsets (106) were compared for genetic variation at 30 loci for blood proteins. ‘Malic enzyme’ and NADH diaphorase I polymorphism occur in Merinos but not in Poll Dorsets, whereas both breeds are polymorphic for haemoglobin, erythrocyte X-protein, serum esterase, catalase and transferrin, although the breeds differ in the presence or absence of certain rare transferrin variants. Poll Dorsets but not Merinos have genetic variation of erythrocyte pyruvate kinase at low gene frequencies; Merinos but not Poll Dorsets have genetic variation of two erythrocyte Gly-Leu peptidases, glucosephosphate isomerase, superoxide dismutase, and NADH diaphorase II, all at low gene frequencies (P < 0·05).Using Masatoshi Nei's (1972, 1976) standard genetic distance, over all 30 loci, to calculate the time of divergence of the two breeds, we obtained t = 69700 years – whereas sheep are believed to have been domesticated by man for not more than 11000 years, and ancestors of the British breeds and of the Merino have probably not been separated for more than 2000 years. Several possible explanations for this discrepancy are discussed, including the accuracy of the coefficient of codon change (α), changes in population size and structure, selection, and additional hybridization in the ancestry of the Merino.

The Enzymic Derivation of Citrulline Residues from Arginine Residues In Situ during the Biosynthesis of Hair Proteins that are Cross-Linked by Isopeptide Bonds

Abstract: An enzymic activity present in hair follicles is described that can convert arginine residues to citrulline residues in proteins in situ. The Ca2+ dependent enzyme activity has been detected in hair follicle extracts but not in similar extracts of serum, liver or brain. The enzyme appears to act on proteins other than hair proteins and the citrulline produced can be quantitated in acid hydrolysates by a colorimetric procedure. the formation of citrulline has been confirmed by amino acid analysis and does not appear to be related to the formation of isopeptide linkages which is catalysed by the transamidase present in hair follicles.