Showing papers by "Macquarie University published in 1987"

Late Paleozoic glacial episodes in Gondwanaland reflected in transgressive-regressive depositional sequences in Euramerica

Abstract: The Late Paleozoic glaciation of Gondwanaland comprised two short episodes, in the Famennian (I) and Visean (II) confined to Brazil and adjacent northwest Africa, and a long episode that started in the Namurian (IIIA) of eastern Australia and Bolivia/Argentina, expanded to cover much of Gondwanaland in the Stephanian/Asselian (IIIB), and collapsed in the early Sakmarian (IIIC). Dropstones in eastern Australia indicate that small ice centers lingered to the Kazanian. Across the belt of low latitudes north of Gondwanaland, short-ranging fossils in widespread shallow-marine and paralic deposits indicate synchronous deposition of transgressive-regressive sequences in different parts of Euramerica. These sequences correlate with glacial events in Gondwanaland at three levels: (a) four major regressions in Euramerica, in the Famennian (1), Visean (2), Namurian (3), Stephanian (4), and the Tastubian transgression that preceded the Sterlitamakian regression (5), also recorded in Gondwanaland, correlate with glacial episodes I, II, and IIIA, IIIB, and IIIC; (b) the time-interval of cyclothemic deposition in Euramerica (Brigantian or latest Visean to Sterlitamakian) correlates with that of glacial episode III; and (c) the dominant period of the Euramerican cyclothems, as estimated from the Middle and Late Pennsylvanian deposits of the mid-continent of North America, and of the thickest known Gondwanaland glacigenic sediment (the earliest Permian Lyons Group of Western Australia) is 0.4 Ma, equivalent in turn to the long orbital-eccentricity period of the Quaternary ice age, and the dominant period of fluctuation of the late Miocene Antarctic ice cap. The three levels of correlations confirm Wanless and Shepard9s (1936) hypothesis that the Late Paleozoic cyclothems are controlled largely by sea-level fluctuations related to the Gondwanaland glaciation.

Intergroup behaviour, self-stereotyping and the salience of social categories

Abstract: Recent research (Hogg & Turner, 1985a, b) favours a social identity rather than group cohesiveness analysis of group behaviour and psychological group formation. It is argued that individual behaviour is transformed into group behaviour by the cognitive process of self-categorization, and that the content of the behaviour depends upon the particular social categorization being employed. The present article examines self-categorization theory by experimentally varying sex-category salience for 60 male and 60 female British university students, and monitoring the effects on self-stereotyping (self-description in terms of an individual's situation-specific own-sex stereotype) and other behavioural and evaluative measures of group behaviour. It was predicted that under conditions theoretically expected to accentuate the salience of sex (intersex collective encounter as opposed to intrasex dyadic encounter), self-categorization, self-stereotyping and group behaviour should occur, and that the specific content of this behaviour would be predictable from the nature of the social relations between the sexes. The results revealed that increased salience was associated with self-categorization and self-stereotyping, and that under these conditions males were less ethnocentric and experienced higher self-esteem than females. These findings are consistent with the hypotheses, and thus provide evidence for both self-categorization theory and the related salience hypothesis upon which the experimental operationalization of salience was based. Suggestions are made for further research.

Clovers secrete specific phenolic compounds which either stimulate or repress nod gene expression in Rhizobium trifolii

Abstract: Rhizobium trifolii mutants containing Escherichia coli lac gene fusions to specific nodulation (nod) genes were used to characterise phenolic compounds secreted from the roots of white clover (Trifolium repens) plants. These compounds either had stimulatory or inhibitory effects upon the induction of the nod genes. The stimulatory compounds were hydroxylated flavones and the most active compound was 7,4'-dihydroxyflavone. The inhibitory compounds present in white clover root exudates were umbelliferone (a coumarin) and formononetin (an isoflavone). Transcriptional activation of nod gene promoters in response to short exposures (3 h) of 7,4'-dihydroxyflavone was growth phase dependent; cells in early log phase were highly responsive to flavone additions in vitro and nod gene induction could be detected within 20 min of exposure at 5 x 10 M. Cells in other growth phases were generally unresponsive. A 10-fold molar excess of umbelliferone to 7,4'-dihydroxyflavone resulted in complete inhibition of nod gene induction. Some commercially-obtained flavones were found to have weak stimulatory activity but could also inhibit nod gene induction by more effective stimulatory compounds. Strong stimulatory and inhibitory compounds all possessed a 7-hydroxy moiety and showed other structural similarities. This suggested that there was one binding site for these compounds. Because the response to these compounds was rapid, we propose that these phenolics act at the bacterial membrane or that an active uptake system is involved.

Is the continental Moho the crust-mantle boundary?

Abstract: Studies of high-pressure xenoliths suggest that mafic rocks are dominant in the lower crust and abundant in the uppermost mantle, beneath most continental areas. Xenolith data allow construction of geotherms and stratigraphic profiles and provide lithological constraints and physical parameters for realistic interpretations of geophysical data. In continental regions of high heat flow, the Moho, as defined by seismic refraction data, may lie deeper than the crust/mantle boundary. The seismic differences recorded for cratonic vs. “hot” lower crust/upper mantle sections may be explained by temperature variations alone and do not require large lithological differences.

Teachers’ Attitudes Towards the Integration of Disabled Children into Regular Schools

Abstract: Regular and resource teachers from New South Wales government and nongovernment schools were surveyed to elicit their attitudes towards the integration of individual disabled chldren, the support services currently provided and the skills considered essential for teachers of mainstreamed atypical students. Differences among sub‐groups of teachers and between teachers and principals who had completed the same questionnaire in a previous study were also examined. Results indicate that teachers’ attitudes to the integration of individual disabled children reflect lack of confidence both in their own instructional skills and in the quality of support personnel currently provided to them. They are positive about integrating only those children whose disabling characteristics are not likely to require extra instructional or management skills on the part of the teacher. However, teachers’ attitudes may be significantly modified by their pre‐service training and the nature of their subsequent professiona...

Graphical estimation of sky view-factors in urban environments

Abstract: Description d'une technique permettant d'estimer les facteurs de vision du ciel dans des localisations urbaines une fois que l'azimuth et les angles d'elevation des bâtiments environnant sont connues

Molecular characterization of tomato fruit polygalacturonase

Abstract: Using the expression vector λgt11 and immunological detection, cDNA clones of an endopolygalacturonase gene of tomato (Lycopersicon esculentum Mill.) were isolated and sequenced. The 1.6 kb cDNA sequence predicts a single open reading frame encoding a polypeptide of 457 amino acids. The PG2A isoform of tomato fruit endopolygalacturonase was purified and 80% of the amino acid sequence determined. The amino acid sequence predicted by the cDNA sequence was identical to the amino acid sequence of the PG2A isoform. The position of the codon for the N-terminal amino acid of mature PG2A in the open reading frame indicates the presence of a 71 amino acid N-terminal signal peptide which is post-translationally processed. The C-terminus of purified PG2A occurred 13 amino acids before the stop codon in the cDNA suggesting that C-terminal processing of PG2A may also occur. The nucleotide and amino acid sequence data predict a mature protein of 373 amino acids and a polypeptide molecular weight of 40279. The sequence contains four potential glycosylation sites. Northern analysis detected endopolyga-lacturonase mRNA in stage 3 (turning) and stage 6 (red) ripening fruit, but not in leaves, roots, or green fruit of normal cultivars or in mature fruit of the rin mutant.

Categorization skills and receptive language development in autistic children.

Abstract: The category knowledge and receptive language skills of 16 autistic, mentally retarded, and normal children were assessed. The autistic children's knowledge of function, form, and color categories was comparable to that of the mental- age- matched mentally retarded and normal comparison groups. Category knowledge and receptive language were more closely associated for mentally retarded and normal children than for autistic children. The findings indicate that category knowledge is not sufficient for the development of receptive language in autistic children.

Orientations to the future: A comparison of adolescents in Australia and Singapore

Abstract: Using an event-listing approach, this study examined the personal and societal future orientations of 15-year-old males and females in Singapore and Sydney. Three aspects were examined: content, affect, and time span. Overall, the study found that adolescents perceived their personal and societal features in separate noninterlocking planes, seeing more pleasant, proximal, personal futures, and more unpleasant, distal, societal futures, especially in relation to nuclear war and political problems. Demographic and personal construct variables influenced this general pattern of future orientation.

Namurian uplift in Australia and South America triggered the main Gondwanan glaciation

Abstract: The Permo-Carboniferous glacigenic sediment at the base of the Gondwanan basins reflects the culmination1,2 of the glacial episode that started in Australia and southern South America in the Namurian, after two local episodes in northern South America and adjacent Africa in the Visean and latest Devonian3 (Fig. 1). Here we show that the start of each episode was associated with orogenic uplift of the bordering regions: northern South America and adjacent Africa in the latest Devonian and Visean, and southern South America and eastern and central Australia in the Namurian. All areas, except southern South America in the Namurian, were at mid- (and not high) latitudes. Thus, we show that whereas the first order control of glaciation was the configuration of the continents and oceans during the closing of Palaeo-Tethys, orogenesis provided a second order control by the accumulation of ice about bordering uplifts during the three glacial episodes.

Stimulus omission and dishabituation of the electrodermal orienting response: the allocation of processing resources.

Abstract: The present research investigated the effects of stimulus omission on electrodermal orienting, dishabituation. and the allocation of processing resources as assessed by reaction time (RT) to a secondary probe stimulus. All experiments employed 33 tone-light or light-tone (S1-S2) pairings, and for experimental groups, S2 was omitted on 4 trials, experiment 1 (N = 24) demonstrated reliable electrodermal responding when S2 was omitted for a trial, and subsequent dishabituation when S2 was then re-presented after SI on the immediately following trial. Experiment 1 (N=96) employed probe RT as the dependent variable. White noise probe stimuli were presented 300 ms or 1300 ms following the omission of S2 and following its onset on re-presentation trials. Reaction time to probes presented during S2 omission was slower in experimental groups than in control groups. Reaction time on S2 re-presentation trials was also slower in experimental groups than in control groups, but only when S3 was a tone. Experiment 3 (N=48) employed auditory and visual probes presented 1300 ms following S2 omission and S2 re-presentation, and measured both electrodermal activity and probe RT, Some evidence of electrodermal omission responding and dishabituation was obtained. Reaction time was again slowed during the omission and re-presentation of S2. regardless of the modality of S2 and regardless of the modality of the probe. The results are interpreted as consistent with an information-processing approach to orienting and habituation in that they indicate that both the omission and re-presentation of an expected stimulus command processing resources.

The effect of fire frequency on the sclerophyll vegetation of the West Head, New South Wales

Abstract: The effect of fire frequency on the relative abundance of obligate-seeders and vegetative-regenerators was studied in 15 pairs of sites on the West Head, NSW. Each site pair consisted of a site which had been burnt frequently over the past 20 years and a nearby site which had been burnt less frequently. The data were collected in two phases. First, the relative abundance of the two overall groups of vegetative-regenerators and obligate-seeders was recorded by measuring the projective cover of live foliage. The presence or absence of particular species was then measured. For all the site pairs the projective cover of live foliage of obligate-seeders was dramatically less in the frequently burnt sites. Some obligate-seeder shrub species were absent from frequently burnt sites and the vegetation structure was simplified. In 11 of the 15 site pairs there was an increase in the projective cover of live foliage of vegetative-regenerators in the frequently burnt sites, while in the remaining four site pairs there were no significant differences between the infrequently and frequently burnt sites. Overall, the increases in the relative abundance of vegetative-regenerators made by high fire frequencies were not as large as the decreases in the relative abundance of obligate-seeders.

The Role of Accounting Information, Environment and Management Control in Multi-National Organizations

Abstract: The results are reported of a replication and extension of the study by Brownell [1985], which focused on the effects of environmental complexity and dynamism on the use of accounting-based controls in the U.S. parent company of a large multi-national organization. The study reported here examines the Australian subsidiary of the company, and its results confirm previous findings, indicating that both job satisfaction and performance are enhanced in circumstances where heavy reliance on accounting-based controls is confined to situations of low environmental complexity. The results also indicate that non-accounting, “behavior” controls have a role in the foreign subsidiary but take on a form other than the placement of U.S. nationals in senior management positions in the subsidiary. Differences in the environment faced by the parent and subsidiary also produced predicted differences in reliance on accounting measures in performance evaluation.

Growth and concentration of fibrous sillimanite related to heterogeneous deformation in K-feldspar-sillimanite metapelites

Abstract: In foliated K-feldspar-sillimanite metapelites, fibrous sillimanite is commonly concentrated in folia that anastomose between lenticular pods of coarser-grained aggregates rich in quartz, feldspar and biotite, with or without garnet, cordierite and residual andalusite. Many of the folia appear to be limbs of crenulation microfolds. The sillimanite concentrations may be due largely to the ability of fibrous sillimanite aggregates to undergo strong non-coaxial deformation by grain-boundary sliding (‘fibre sliding’;) without appreciable build-up of dislocations, whereas other minerals are unstable in these zones and so concentrate in lower-strain interfolial zones. Initiation, and especially concentration of the sillimanite in folia, may be assisted by fluid flow and local base-cation leaching, whereby minerals unstable in zones of strong non-coaxial strain are dissolved and removed from these zones.

Variability in body shape perception in anorexic, bulimic, obese, and control subjects

Abstract: Differences in the variability of the judgements of body shape were studied in anorexic, bulimic, obese, and control subjects. The judgements of control subjects were found to be more accurate and less variable than those of the clinical groups, and the distribution of their scores was leptokurtic and almost symmetrical compared with the clinical groups' distributions of scores which were platykurtic and positively skewed. More clinical subjects than controls both underestimated or overestimated their body sizes by 15% or more. Significantly more variability was found among the scores of bulimics than anorexics and among the scores of the obese than the anorexics, but not between the obese and the bulimics, who showed the greatest variability of all. The results are discussed in terms of their consistency with other research findings and their significance for treatment.

The language of legislation

Abstract: The characteristics of the language of legislation are derived from its role in the institution of law. An analysis of the institutional context reveals links among history, social function, participant roles, accepted goals of legislation, and language use. The nature of an Act of Parliament as a perpetual speech act creates a frozen authoritative text so that the language itself becomes a component of the law. If legislation is to be both stable and flexible, institutional communicative strategies are required to organise linguistic means to these sociolinguistic ends. (Law, legislation, register, speech acts, communicative competence, communicative strategies)

Cellular basis of allograft rejection in the solitary urochordate,Styela plicata

Abstract: The response of various cell types to first-set and secondary allografts in S. plicata was tested. The data implicate lymphocyte-like cells in allograft rejection. They were the only cells to specifically invade incompatible allografts and the surrounding tissue prior to rejection. This influx coincided with the destruction of other cells within allografts and thus may have been responsible for graft loss. Other cell types did, however, undertake non-specific responses to grafts which were probably stimulated by wounding. These results are discussed in terms of the evolution of the vertebrate immune system.

Productive efficiency and ownership of urban bus services

Abstract: The established ownership mix of urban bus operations in Australia provides a unique opportunity to investigate the productivity differences between public and private bus service supply. Using duality theory in economics which links economic indices of factor productivity to the cost structure of a firm, we develop empirical measures of total and partial productivity of inputs, and adjust the differences for the effects of ownership status and operating environment. The evidence supports the notion that private supply of public passenger transport in general has performed more efficiently in the past than public supply, although the differences in productivity need not continue in the future.

Population structure and reproductive status of two Banksia shrubs at various times after fire

Abstract: Populations of the obligate-seeder, Banksia ericifolia, were even-aged. Seedling recruitment occurred only after fire. Mean genet size (height + canopy diameter; H + D) increased progressively with elapsed time since fire in stands last burnt 2-23 years before 1981. Populations of a co-occurring resprouter, B. oblongifolia, were mixed-aged. Genet size varied significantly between stands, but this variation was not explained by regressions of H + D on years since fire. In addition B. oblongifolia seedlings were recruited both after fire and in patches of heath unburnt for 16 years. Most flower and seed production in B. oblongifolia occurred in the stands last burnt less than 10 years pre viously. More than 30% of genets had not produced cones since the last fire, irrespective of how many years had elapsed. In contrast, few B. ericifolia genets had produced cones five years after fire, but by 16 years after fire nearly 100% had. Overall, about 51% of B. ericifolia inflorescences and about 28% of B. oblongifo lia inflorescences set seed. The number of seeds in seed-bearing cones was not significantly different between species. Resprouting B. oblongifolia genets began flowering sooner after fire, but B. ericifolia subsequently over took them in accumulating a bank of serotinous seeds. In the stand unburnt for 23 years the largest B. ericifolia genets had more than twice as many cones as the largest co-occurring B. oblongifolia. However, when accumulated cone production was compared for genets of equal H + D over all stands, there was no difference between species.