Showing papers by "University of Canterbury published in 1969"

Strength of Concrete Filled Steel Tubular Columns

Abstract: The ultimate strength of axially and eccentrically loaded steel tubular columns covering a wide range of slenderness ratios was investigated. Hollow steel tubes were tested and compared with concrete filled steel tubes. It was found that the buckling load of the axially loaded long columns can be accurately predicted by summing the tangent modulus loads for the steel tube and the concrete core acting as independent columns. The effect of slenderness ratio on the lateral pressure exerted by the tube on the concrete was examined. Lateral pressure is exerted when the concrete commences to increase in volume at high strains and results in an increase in strength of the concrete. Buckling will occur before the longitudinal strain becomes sufficiently high to cause the concrete to increase in volume. For eccentrically loaded columns constructed from steel tubes infilled with concrete, it was found that a straight line interaction formula using the ultimate axial load and the ultimate flexural capacity of the sections predicted failing loads.

Relationships between grain size, size-sorting, and foreshore slope on mixed sand - shingle beaches

Abstract: The variation of mean grain size (Mzφ), sorting (σI), and beach face slope over mixed-sand shingle beaches at two areas along the east coast, South Island, New Zealand, it analysed in order to determine the nature of the relationships between these three variables. The study is confined to mean grain sizes between 0.25 and 16.0 mm, and the sorting and slope values associated with this range of sizes. Trend analysis of the data has been performed by fitting curves with the aid of a computer. As distinct from the linear average relationship betweeen size and slope distinguished by many workers, it is demonstrated that for given beaches curvilinear trends in size/sorting are reflected in slope/size relationship. Thus, the best sorted sediments are found to be associated with the steepest gradients on the curves, while zones of poor sorting are associated with “plateaus” in the size/slope trend. It is suggested that size is the primary control of sorting trends in the sediments examined whilst hydrau...

Nitrogen Fixation by Gunnera–Nostoc Symbiosis

Abstract: THE genus Gunnera (Haloragaceae) contains forty species, all herbaceous, ten being endemic to New Zealand. Glands occurring at the bases of leaves become invaded by the blue-green alga Nostoc puntiforme1,2 which becomes intracellular3 and is capable of nitrogen fixation in culture2,4. Algal glands have been described for several New Zealand species5,6.

Seasonal reproductive periodicity in the male Australian Brush-tailed possum (Trichosurus vulpecula)

Abstract: The reproduction of the possum, Trichosurus vulpecula (Kerr), was investigated on Banks Peninsula, Canterbury, from 1963 to 1965. The majority of births occur in the autumn, but there is a minor breeding season in the spring. After undergoing an anoestrous period during the summer most females enter oestrus around April. A small proportion of females give birth to a second young during September or October. Reproductive periodicity was also found to occur in the male possum. Although spermatogenesis continues throughout the year in the sexually mature animal there is a marked change in the size of the prostatic urethra at particular periods of the year which correspond to those in which the majority of females are undergoing oestrus. The mean weight of the prostate shows a sixfold increase during the autumn. However only very small changes take place in the size of the testis and epididymis. Changes in size and activity of the prostate correspond with marked changes in the interstitial tissue of the testis. Leydig cells, responsible for the secretion of testosterone, show a great increase in number in animals in which the prostate is enlarged. Associated with the growth of the prostate are changes in the behaviour of the possum. The body weight and fat deposits of the male possum drop markedly at the time of the autumn breeding season.

Predation By Mononchoides Potohikus (Nematoda: Diplogasteridae) in Laboratory Culture

Abstract: Cultures of Mononchoides potohikus have been maintained on agar plates with a bacterium (Bacillus cereus var. mycoides). Also M. potohikus has been found to be a facultative predator, preying on a wide range of nematode species. The predation rate of females is independent of the prey species, the presence of old tracks of the prey species, and the presence of a bacterial film. Predation rate is not affected by satiation but is dependent on prey density and is affected by the presence of water on the agar plate. The predation rate of the apparently non-functional males is significantly greater than that of females.

Social facilitation of locomotion and exploration in rats

Abstract: Male white rats engaged in more locomotion and less defaecation and freezing in an open field when in the company of another male rat than when alone. They also exhibited proportionally more sniffling and less tooth grinding and chattering when in the same square of the aparatus as their partners than when in different squares. It was concluded that the presence of a second rat somehow reduced the aversive nature of the experimental environment.

Larval life span of the echinoid evechinus chloroticus (val.)

Abstract: Summary Newly metamorphosed Evechinus chloroticus (Val.) were observed in three larval cultures 36, 30, and 28 days after fertilisation, indicating that the free swimming larval life may last about 1 month.

Distribution and abundance of the Weddell seal in the western Ross Sea, Antarctica

Abstract: Summary The distribution and abundance of the Weddell seal (Leptonychotes weddelli Lesson) in the fast ice and pack ice of the western Ross Sea, Antarctica, were investigated during 1967 and 1968 from icebreakers and accompanying helicopters. It was estimated that there were about 50,000 Weddell seals in the western Ross Sea between Cape Adare and McMurdo Sound. Weddell seals appear to breed mainly in the fast ice along the Victoria Land coast and less frequently in some nearby areas of pack ice. Fast ice is preferred to pack ice. Most Weddell seals in the pack ice were adults. General observations on the distribution of crabeater, leopard, and Ross seals are included.

The influences of birth order, family size and sex differences on risk-taking behaviour.

Abstract: The effects of birth order, family size and sex differences on risk-taking behaviour were examined. The subjects were 84 10–12-year-old children of both sexes. The risk-taking task was derived from Slovic (1966). Three hypotheses were tested. First-born, youngest and intermediate siblings did not differ in the amount of risk they accepted. Subjects from smaller families accepted less risk than subjects from larger families (P0<05). Male and female subjects did not differ significantly in the amount of risk they accepted. The major finding from the study suggests the importance of family size as a factor in psychological research dealing with ecological variables.

A learning machine with monologue

Abstract: The learning machine STeLLA has been developed considerably since it was first described in 1962. Although it has not been built in entirety, it has been simulated on computers in many different forms and with many different problems; special circuits have been developed for its construction. The need to give the machine a “monologue” ability arose because the machine cannot learn to solve problems for which the input to the machine is inadequate to distinguish successive steps made by the machine. A simple example of this is the problem of learning to perform a sequence of actions when the sequence is not related to information received by the machine from its problem environment. In this paper an introductory description of the STeLLA machine is given with the help of a particular problem which is then used to illustrate the generation of control policies by a dual machine. The dual STeLLA comprises two interdependent STeLLA machines or STeLLAments; one interacts directly with the problem environment, while the second STeLLAment interacts with an auxiliary “vocal” environment to provide monologue. Monologue is used to supplement the information from the problem invironment with information from the vocal environment. The STeLLAment interacting directly with the vocal environment has its input supplemented by information from the control policy of the other machine. The two machines are co-ordinated further by giving reward to the dual machine as a whole. The procedure of counting is the kind of monologue which can be used to distinguish a sequence of steps that cannot be distinguished by successive inputs from the problem environment. This is illustrated in the paper by considering a problem that requires STeLLA “to walk across a dark courtyard”. Monologue is not restricted to such counting of steps, but can take the form of more sophisticated “symbol” sequences. By allowing an operator to inject sequences into the monologue of the machine, an elementary form of dialogue could be set up. It would be a special feature of the dialogue that no predetermined language was imposed on the participants. Examples of the use of monologue have been worked out and more complicated situations are being programmed for computer simulation both in the monologue and dialogue form.

Rayleigh hypothesis, the extended-boundary condition and point matching

Abstract: A recent suggestion, that the Rayleigh hypothesis for electromagnetic scattering is exact, is shown, by counterexample, to be questionable. A point-matching solution for the surface current density (not the scattered field) is shown to be rigorously based. The solution is similar to that for the scattered field derived from the Rayleigh hypothesis.

Nitrogen Complexes as Models for Nitrogenase with Nitrogen on the Active Site

Abstract: NITROGEN gas reacts in mild conditions in protic media to give the nitrogen complexes [CoH(N2)(PPh3)3]1, and [Ru(NH3)5(N2)]X2 (X = mono anion)2, and related complexes, but the complexed nitrogen molecule has not yet been reduced to ammonia3. Nevertheless, the mechanism of nitrogen uptake in the formation of these complexes may represent the process by which nitrogen is bound in nitrogenase, and the reduction to ammonia could occur in nature by protonation of the complexed nitrogen with simultaneous influx of electrons from the metal. We have therefore studied quantitatively the reactions with strong acids of [CoH(N2)(PPh3)3]1, the substance formulated as [Co(N2)(PPh3)3]4, trans-[IrCl(N2)(PPh3)2]5, and [Ru(NH3)5-(N2)]X2 (X = Cl or BF4)6,7. If protonation occurred, some reduction of the nitrogen with simultaneous oxidation of the metal would be expected. We have found that in general there is oxidation of the metal by the acid, but it leads to nitrogen evolution, often together with hydrogen, and no ammonia.

Environmental temperatures of tertiary penguins.

Abstract: Marine paleotemperatures, determined by oxygen isotope measurement, show that Australasian Tertiary penguins, including giant forms, lived in warm to tropical environments. Evolution from smaller species also occurred in warm environments. Mid-Tertiary fluctuations of sea temperature were controlled by alternating uplift and erosion of "Tasmantis," an unstable meridional landmass occupying and extending beyond the present position of New Zealand.

The configurations (d + s)N and the group R6

Abstract: 2014 A simple method of computing the branching rules arising in the chain of groups : R24 ~ SU2 Sp12 ~ SU 2 SU2 (R6 ~ R5 ~ R3) used in classifying the states of the (d + s)N configurations is presented in addition to an unambiguous method for analyzing Kronecker products for R6 using the known isomorphism between R6 and U4. Several corrections to earlier works are noted. Finally, an explicit formula for the Kronecker products in R4 is given.

Streambed investigations in a small mountain catchment

Abstract: A modern accelerated erosion phase, post-dating the beginning of European-style farming in New Zealand, is associated with a depletion in the vegetation cover of Centre Creek catchment (Broken River area, South Island), and has caused substantial modification of streambed forms. An increase in the supply of debris to stream beds resulting from concentrated gullying, mass movement processes, and snow avalanche activity has caused (a) changes in the shape of the longitudinal profiles, (bl the formation of alluvial, valley bottom terraces, and (c) general widening and aggradation of the stream bed in the lower reaches. Some of the streambed processes operating in Centre Creek are briefly described.

Qualitative and Quantitative Aspects of Thyroxine Metabolism in Sheep

Abstract: Qualitative and quantitative aspects of thyroxine degradation and excretion in adult, intact and biliary-fistulated sheep in a near-basal state are reported. Thirty-eight per cent of the T4 metabolized was deiodinated, about 56% of this iodide being taken up by the thyroid, 36% being excreted in urine and 8% in feces; 62% of the T4 secreted was excreted unchanged or as a thyroxine conjugate. Of this, 39 % was in bile, 22 % in urine and 39 % was excreted in feces from a nonbiliary source. Although T4 secretion per unit metabolic body mass (weight0–7) is much higher in sheep than in man and some other domestic animals, T4 deiodination/unit metabolic body mass is very similar to other species. This is consistent with investigations on laboratory animals which have shown that T4 excreted in feces has not influenced metabolism. Therefore, it is suggested that, in investigations in which thyroid function is correlated with some metabolic response, the large and potentially variable fraction excreted unchanged o...