Showing papers by "University of Auckland published in 1982"
TL;DR: In this article, the authors outline the dynamics of this process, particularly in the context of the South Pacific, and show that the superior entrepreneurial skills, resources, and commercial power of metropolitan companies enable them to dominate many Third World tourist destinations.
833 citations
TL;DR: In this article, the authors look at the effect of intracluster correlation on standard procedures in linear regression and show that the size of the effect tends to be smaller than the corresponding effect on the variance of an estimated mean in two-stage sampling.
Abstract: We look at the effect of intracluster correlation on standard procedures in linear regression. The ordinary least squares estimator, , of the coefficient vector performs well in most cases but the usual estimator of cov() and procedures based on this such as confidence intervals and hypothesis tests can be seriously misleading. The size of the effect, however, tends to be smaller than the corresponding effect on the variance of an estimated mean in two-stage sampling provided that the cluster sample sizes are approximately equal.
244 citations
TL;DR: The results indicate that the chief questions concerning the structuring of subtidal algal communities are demographic in nature and that an assessment of the status of individual organisms, rather than biomass or productivity, is the appropriate approach to resolve these questions.
216 citations
TL;DR: The isolation of specific T cell growth factors termed interleukin 2 (IL 2) is changing the approach to understanding T cell function and has allowed the establishment of a number of human and murine T cell lines.
Abstract: The isolation of specific T cell growth factors termed interleukin 2 (IL 2) is changing the approach to understanding T cell function. This class of growth factors has allowed te establishment of a number of human and murine T cell lines. We summarize the biochemical properties of human and murine IL 2. Studies have been initiated to isolate mRNA encoding for IL 2. Such RNA can be translated in rabbit reticulocyte lysates yielding IL. 2. This RNA may be useful for the development of probes to isolate lymphokine genes.
165 citations
TL;DR: In this paper, the problem of defining Cauchy sequence and completeness in quasi-pseudo-metric spaces was considered, and the definitions proposed allow versions of such classical theorems as the Baire Category Theorem, the Contraction Principle and Cantor's characterization of completeness to be formulated in the quasi-semi-measure setting.
Abstract: This paper considers the problem of defining Cauchy sequence and completeness in quasi-pseudo-metric spaces. The definitions proposed allow versions of such classical theorems as the Baire Category Theorem, the Contraction Principle and Cantor's characterization of completeness to be formulated in the quasi-pseudo-metric setting.
164 citations
TL;DR: A family of compounds which appear to bind reversibly to double stranded DNA without intercalation between DNA base pairs has been defined and binding of drugs to the minor groove of the DNA double helix appears to be the most likely mechanism for the antitumour action of these compounds.
Abstract: A family of compounds which appear to bind reversibly to double stranded DNA without intercalation between DNA base pairs has been defined. Methods are described by which this non-intercalative binding can be characterised using ultraviolet spectrometry, fluorimetry with ethidium as a probe, viscometry and other hydrodynamic techniques, circular dichroism and nuclear magnetic resonance spectrometry. Antibiotics which fall into this family include the antibiotics distamycin A, netropsin, mithramycin, chromomycin and olivomycin. Synthetic antitumour agents include diarylamidines such as berenil, phthalanilides, aromatic bisguanylhydrazones and bisquaternary ammonium heterocycles. A survey has been made of the general requirements of this family of compounds for DNA binding and biological activity. Binding of drugs to the minor groove of the DNA double helix appears to be the most likely mechanism for the antitumour action of these compounds.
138 citations
TL;DR: In this article, it is argued that the way in which Williamson evaluates efficiency is open to methodological and other objections, and that there is limited empirical support for his hypothesis, and the evidence suggests that the putting-out system was usually able to compete with the factory.
Abstract: An evaluation of the organizational efficiencies of various modes of production by O.E. Williamson has led him to conclude that, given identical technologies, the factory was more efficient than the putting-out system. The superior organizational efficiency of the former, he maintains, was one reason for the transition to factory production during the nineteenth century. This paper challenges that view. It is argued that the way in which Williamson evaluates efficiency is open to methodological and other objections, and that there is limited empirical support for his hypothesis. Given an identical technology, the evidence suggests that the putting-out system was usually able to compete with the factory.
135 citations
TL;DR: It is suggested that the lateral growth of fibrils beyond a diameter of about 60 nm is inhibited by the presence of an excess of hyaluronic acid but that this inhibitory effect may be removed by an increasing concentration of chondroitin sulphate and/or dermatan sulphate.
126 citations
TL;DR: The structures of 13 variants of invertebrate septate junction are reviewed on the basis offreeze-fracture, lanthanum tracer and thin-section studies, and a theory is put forward suggesting that in evolution a change from the septates to the tight junction could simply involve a modification of a ‘membrane spacing factor’, which allows the membranes of adjacent cells to come together at intervals.
Abstract: The structures of 13 variants of invertebrate septate junction are reviewed on the basis offreeze-fracture, lanthanum tracer and thin-section studies. In addition, a simple type ofoccluding junction in the phylum Porifera, a variation of tight junction in the phylum Tunicateand the vertebrate tight junction are covered. All the junctions considered form a belt around the apical circumference of cells lining a lumen or an exterior surface. The large number of these junctions now recognized permits discussion relating to invertebrate classification and suggested phylogenetic relationships, and to the development of intercellular junctions. The relationships revealed are discussed under three headings: Coelenterates and lower invertebrates, Proterostomia (the annelid, molluscan and arthropod lineage) and the Deuterostomia(the echinoderm and chordate lineage). It is proposed that the pleated septate junction of the lower invertebrates resembles that of the hydrozoan rather than anthozoan Coelenterates. This lower invertebrate pleated septate junction occurs in several lower invertebrate phyla including the Annelida (of the proterostome lineage), but also occurs in the Sipunculoidea, a group supposedly on the deuterostome lineage.The proterostome line includes the molluscs and the arthropods, which have the molluscarthropodpleated septate junction. Several variations of the smooth septate junction are alsoseen in Arthropoda. Among the deuterostomes the Chaetognatha have both a paired septatejunction and a pleated junction and are therefore considered to be not very far removed fromthe Sipunculoidea. The echinoderms and hemichordates also have double-septum septatejunctions. In addition however, these two phyla have anastomosing septate junctions thatare very similar, varying only in their final configuration. Of the two, the echinoderm anastomosingseptate junction most closely resembles the tight junction seen in the tunicates, and the Hemichordata are therefore considered to be a lateral development from the main lineof chordate evolution. The tunicates have a tight junction similar to that seen in vertebrates;it is however more ‘leaky’ and has distinctive freeze-fracture characteristics.In the phylum Porifera a form of simple parallel membrane junction appears to serve anoccluding function. This junction has regular intercellular spacing in the absence of any septaand it is suggested that the spacing in septate junctions is probably not dictated by the septa.This interpretation is reasonable particularly when the diversity of septal types in conjunctionwith stable intercellular spacing is considered. Finally, a theory is put forward suggesting thatin evolution a change from the septate to the tight junction could simply involve a modificationof a ‘membrane spacing factor’, which allows the membranes of adjacent cells to come together at intervals, in the normal tight junction pattern.
119 citations
TL;DR: The distribution of fibers in agarose gels has been studied by electron‐microscopic examination of replicas formed from freeze‐fracture surfaces and the results obtained support the model proposed for the gel structure by Arnott et al. (1974).
Abstract: The distribution of fibers in agarose gels has been studied by electron-microscopic examination of replicas formed from freeze-fracture surfaces. For gels set in water, the results obtained support the model proposed for the gel structure by Arnott et al. (1974) of a random array of long, straight, connected fibers, with each fiber having a diameter equivalent to that of an aggregate of approximately 10–30 agarose helixes, depending on the initial agarose concentration. The density of these fibers, their water content, and the total length of fibers per unit volume have been derived from the measured distribution of intersections per unit area of freeze-fracture surfaces. For gels set in the presence of salt, the distribution of fibers becomes distinctly non-Poissonian, leading to larger interfiber spaces and a gel of greater effective pore size. The larger pore size of gels set in the presence of salt also has been revealed by electrophoretic measurements in which the relative migration rates of plasmid DNA molecules of varying conformations have been determined.
108 citations
TL;DR: Litter fall beneath 2 distinct growth forms of the mangrove is seasonal, with peak fall at the time of fruit production in summer, and suggests that, in terms of litter, mangroves may be one of the most productive forest types in New Zealand.
Abstract: The New Zealand mangrove, Avicennia marina var. resinifera, grows close to the latitudinal limit of mangroves. Nevertheless, litter‐fall studies in Tuff Crater, Auckland (36°48’ S, 174°45’ E), using litter‐fall bag and plot techniques, indicate that the mangroves are very productive. Litter fall beneath 2 distinct growth forms of the mangrove is seasonal, with peak fall at the time of fruit production in summer. Beneath the taller mangroves of the creek banks (3.5–4.0 m tall) annual total dry weight of litter fall is estimated as 8.10±2.74 t ha‐1 a‐1, whereas beneath the lower, stunted mangroves of the flats (<1.0 m tall), the total is estimated as 3.65 t ha‐1 a‐1. The values from the taller mangroves are higher than litter fall recorded beneath Avicennia at similar latitudes in Australia, and lie within the range reported from mangroves in Queensland, Florida, and elsewhere. They suggest that, in terms of litter, mangroves may be one of the most productive forest types in New Zealand. The rate o...
TL;DR: Reefs dominated by red algae, associated with high echinoid densities, are consistent features of the shallow subtidal around northeastern New Zealand and it is suggested that these represent sufficient input into the adult grazing population to maintain the habitat.
Abstract: Reefs dominated by red algae, associated with high echinoid densities, are consistent features of the shallow subtidal around northeastern New Zealand. Factors determining the abundance of juvenile Evechinus chloroticus were investigated in such a habitat. Using a factorial design, a field experiment was used to assess the influence of predators and adult E. chloroticus on juvenile abundance. The use of 2 m2 exclusion cages enhanced juvenile E. chloroticus abundance over a 16 month period, an effect independent of conspecific adults. We attributed this effect to the exclusion of benthic-feeding, predatory fish. Several species forage over the study area at high densities and are known from gut content analysis to prey on juvenile E. chloroticus in the field. Invertebrate predators are at very low densities in the area. The possibility of caging and site artefacts confounding this interpretation is discussed.
TL;DR: In this article, the authors examined airflow using conventional methods together with experimental procedures using SF6 and CCl2F2 tracer gases and found that the rate and direction of airflow are a direct response to a thermally induced disequilibrium in air density between the cave and outside air.
Abstract: Study of cave climates is a neglected aspect of microclimatology. An understanding of the processes that control cave climate is required in the study of cave flora and fauna, thermodynamic conditions for karst processes underground, hydrogeologic features of speleothems as well as human use of caves for recreational and commercial purposes. An understanding of cave airflow is of central importance as the climate of a cave is a function of air exchange with the outside environment. The study site is the Glowworm Cave of New Zealand and is of particular interest because of its heavy visitor use and the presence of climate sensitive cave fauna on which the value of the cave as a tourist attraction depends.
The study examines airflow using conventional methods together with experimental procedures using SF6 and CCl2F2 tracer gases. The results show that the rate and direction of airflow are a direct response to a thermally induced disequilibrium in air density between the cave and outside air. Both diurnal and seasonal patterns in the direction of airflow were identified. Reversal of airflow occurs when the cave to outside air density gradient is zero rather than when thermal conditions of the cave and external air are the same. Major and minor airflow routes through the cave were identified. The results of the gas tracer experiments allowed estimation of rates of air change in different parts of the cave and confirm the marked difference in ventilation that occurs within the cave. Information of this type is important because of the relationship between natural ventilation and CO2 buildup. There is also the effect of ventilation on differences in climate within the cave as the thermal and moisture effects of outside air will not be as pronounced in parts of the cave where air change is limited.
TL;DR: In this article, the applicability of generalized inverses to a wide variety of problems in applied probability where a Markov chain is present either directly or indirectly through some form of imbedding is examined.
TL;DR: In this article, the principle of large-scale anisotropy due to small-scale layering is applied to thermal convection, where the motion takes place in a bounded porous medium heated from below.
Abstract: The principle of large-scale anisotropy due to small-scale layering is applied to thermal convection. The motion takes place in a bounded porous medium heated from below. The medium is periodically layered with respect to permeability and thermal conductivity. The onset of convection as well as slightly supercritical convection are investigated. Anisotropic modelling proves useful even for small numbers of layers as long as the motion is of ‘large-scale convection’ type (Masuoka et al. 1978). The modelling always fails for motion of ‘local convection’ type.
TL;DR: There is considerable stability in the mate recognition system of D. melanogaster in spite of the substantial genetical and morphological differentiation which exists throughout the cosmopolitan distribution of this species.
Abstract: Multiple choice experiments using 29 populations of Drosophila melanogaster from around the world were performed to measure any divergence in the mating system of this species. Courting flies were observed in a total of 691 mating experiments and 9,280 copulations. Only two of the 38 interpopulation crosses exhibited a significant divergence from random mating. However, neither of these represent a trend towards positive assortative mating. This suggests that there is considerable stability in the mate recognition system of D. melanogaster in spite of the substantial genetical and morphological differentiation which exists throughout the cosmopolitan distribution of this species.
TL;DR: Evidence is presented suggesting that mentally retarded and autistic children generally show a poor response to stimulant medication, whereas hyperactive and normal children respond beneficially.
Abstract: An attempt is made to integrate data from a variety of clinical populations and from the animal literature. Evidence is presented suggesting that mentally retarded and autistic children generally show a poor response to stimulant medication, whereas hyperactive and normal children respond beneficially. Cognitive research in mentally retarded and autistic children is reviewed, and it is suggested that both diagnostic groups suffer from attentional difficulties, the mechanisms of which may be very similar. The literature on stimulant-induced stereotypy in animals is discussed, with emphasis on the clinical implications for autism and mental retardation. An attentional model is proposed to account for type of therapeutic response to stimulant medication. This is followed by a possible method for testing the model and by specific predictions relating to subject characteristics and response.
TL;DR: The outcome in childhood schizophrenia may be more favorable than generally assumed, but there is a need for longer and larger studies of carefully diagnosed groups.
Abstract: Schizophrenic children admitted as inpatients to a child psychiatric unit over a 10-year period were reviewed in terms of demographic characteristics, clinical features, and social adaptation using the DSM-III as a frame of reference. Ten children who were first seen at least 1 year previously were followed up and reassessed as regards clinical status and level of adaptive functioning. As in other studies, outcome was related to age at onset, premorbid level of adaptation, rapidly of onset, clinical subtype, and presence of affective symptoms. However, deterioration following the active phase of the illness occurred in only four cases. The outcome in childhood schizophrenia may be more favorable than generally assumed, but there is a need for longer and larger studies of carefully diagnosed groups.
TL;DR: It is suggested that seasonal changes in the abundance of invertebrates occurs independently of the high densities of predatory fish recorded in this habitat.
Abstract: A fauna of small invertebrates in a perennial algal turf habitat showed marked seasonal fluctuations in abundance. These were characterised by a summer (December) peak in the abundance of gammarid amphipods and an autumn (April) peak in polychaete densities. Invertebrate abundance was lowest during the period February-March which coincided with an influx of very high densities of juveniles (0+ year class) of the sparid fish Chrysophrys auratus. Both juvenile C. auratus and also the mullid Upeneichthys porosus achieved their highest densities over coralline turf areas and fed on the associated invertebrates. Gammarid amphipods constituted the main food items of each species. All these observations suggested a key role of fish predators in determining the observed seasonal patterns of invertebrate abundance.This hypothesis was investigated by the use of replicated fish exclusion shields and cages which excluded both species from the algal turf and also permitted an assessment of Upeneichthys porosus feeding in the absence of Chrysophrys auratus. The experiment ran from November until June and covered the period of invertebrate and fish abundance changes. Little evidence of a fish predation effect on either the densities of or the timing of abundance peaks of the invertebrate fauna was detected. Sediment analysis of the cage and control experimental sites revealed no evidence of a cage effect on the microhabitat. It is suggested that seasonal changes in the abundance of invertebrates occurs independently of the high densities of predatory fish recorded in this habitat.
TL;DR: A morphologic model is proposed that provides a mechanism by which these radial arrays can develop passively from the more random, 3-dimensional network of fibers observed in normal articular cartilage.
Abstract: Abnormal softening in articular cartilage is related to the presence of collagen fibers strongly aligned in a radial direction. In this paper, a morphologic model is proposed that provides a mechanism by which these radial arrays can develop passively from the more random, 3-dimensional network of fibers observed in normal articular cartilage.
TL;DR: The formal language studied in this paper contains two categories of expressions, terms and formulas, and an algebraic and model theoretic account of validity are given and an axiomatic system is provided for which they are characteristic.
Abstract: The formal language studied in this paper contains two categories of expressions, terms and formulas. Terms express events, formulas propositions. There are infinitely many atomic terms and complex terms are made up by Boolean operations. Where α and β are terms the atomic formulas have the form α=β (α is the same as β), Forb α (α is forbidden) and Perm α (α is permitted). The formulae are truth functional combinations of these. An algebraic and a model theoretic account of validity are given and an axiomatic system is provided for which they are characteristic. The ‘closure principle’, that what is not forbidden is permitted is shown to hold at the level of outcomes but not at the level of events. In the two final sections some other operators are considered and a semantics in terms of action games.
TL;DR: Five pigeons were trained over 43 experimental conditions on a variety of concurrent variable-interval schedules on which the forces required on the response keys were varied, and overall reinforcement rate and overall force requirement did not affect preference.
Abstract: Five pigeons were trained over 43 experimental conditions on a variety of concurrent variable-interval schedules on which the forces required on the response keys were varied. The results were well described by the generalized matching law with log reinforcement ratios and log force ratios exerting independent (noninteractive) effects on preference. A further analysis using the Akaike criterion, an information-theoretic measure of the efficiency of a model, showed that overall reinforcement rate and overall force requirement did not affect preference. Unlike reinforcement rate changes, force requirement increases did not change the response rate on the alternate key, and an extension of Herrnstein's absolute response rate function for force variation on a single variable-interval schedule is suggested.
TL;DR: The evidence from this study supports the conclusion that feeding preferences by echinoids are labile and do not clearly exert the major influence on the removal of plants from natural stands.
Abstract: Feeding choice of the echinoid Evechinus chloroticus was examined for six fucoid and one laminarian species of algae. Three experiments were conducted to determine the algal choice by echinoids under controlled conditions. In the first experiment, the seven algal species were presented to echinoids in laboratory conditions. The second experiment had replicates of the algal species placed randomly on a subtidal rocky reef where echinoids were abundant and randomly dispersed. For the third experiment, which was also field-based, replicates of one highly-ranked species, Ecklonia radiata, were presented to naturally dispersed Evechinus. In addition, a series of controlled observations was used to examine the order in which echinoids removed algae from mixed species stands on subtidal boulders and to determine if this was related to the experimentally demonstrated choices of algal species. The results of the first two experiments showed that there were differences between algal species in the amount of material grazed by echinoids. Rankings of algal species from the field experiment were not correlated with rankings from the laboratory experiment. The order of removal of algal species from natural stands was correlated with the laboratory-based experimental rankings of algal species, but not with the rankings from the field-based experiment or with algal species availability. There were differences between algal species in their vulnerability to grazing by echinoids, as measured by regression analyses on the amount of material grazed from algal replicates vs. the number of attached echinoids. Within each species, echinoid numbers exerted a non-linear effect on the removal of algal material. In the third experiment, where only one species of algae was presented, the echinoids still distributed themselves non-randomly amongst replicates, aggregating on some samples. Data on the finer scale distribution of algal species over the entire subtidal reef on which these experiments and observations were conducted indicate that Evechinus are not often presented with a choice of adult plants of several different species in natural stands. The evidence from this study supports the conclusion that feeding preferences by echinoids are labile and do not clearly exert the major influence on the removal of plants from natural stands. Preference, as determined from experimental rankings of algal species, is only one of a number of factors which may affect the removal of algae by echinoids. Other important factors are the density of echinoids present, algal susceptibility to removal, and the distribution and abundances of the various algal species and echinoids relative to each other. It is suggested that algal life history characteristics may be unaffected by echinoids and that coevolutionary arguments are not appropriate for describing echinoid-algal interactions.
01 Oct 1982
TL;DR: In this paper, the analysis of a commonly used coaxial-line/rectangular-waveguide junction, formed by the coaxial line entering the broad wall of the waveguide, is outlined.
Abstract: The analysis of a commonly used coaxial-line/rectangular-waveguide junction, formed by the coaxial line entering the broad wall of the waveguide, is outlined. The theory is based on a model closely related to the physical situation and does not require the use of empirical factors. Numerical results can be evaluated directly from the theoretical expressions, and aspects of such evaluation are briefly discussed. Extensive comparison of theoretical and experimental results has shown the analysis to be very accurate. An equivalent circuit for the junction, applicable to the case where the TE10 mode is the only propagating waveguide mode, is also reported.
TL;DR: The effects of component duration on multiple schedule performance cannot be interpreted as changing sensitivity to reinforcement nor to changing bias, but schedule reversals at short component durations eliminated the response rate increases.
Abstract: Four experiments, each using the same six pigeons, investigated the effects of varying component durations and component reinforcement rates in multiple variable-interval schedules. Experiment 1 used unequal component durations in which one component was five times the duration of the other, and the shorter component was varied over conditions from 120 seconds to 5 seconds. The schedules were varied over five values for each pair of component durations. Sensitivity to reinforcement rate changes was the same at all component durations. In Experiment 2, both component durations were 5 seconds, and the schedules were again varied using both one and two response keys. Sensitivity to reinforcement was not different from the values found in Experiment 1. In Experiment 3, various manipulations, including body-weight changes, reinforcer duration changes, blackouts, hopper lights correlated with keylights, and overall reinforcement rate changes were carried out. No reliable increase in reinforcement sensitivity resulted from any manipulation. Finally, in Experiment 4, reinforcement rates in the two components were kept constant and unequal, and the component durations were varied. Shorter components produced significantly increased response rates normally in the higher reinforcement rate component, but schedule reversals at short component durations eliminated the response rate increases. The effects of component duration on multiple schedule performance cannot be interpreted as changing sensitivity to reinforcement nor to changing bias.
TL;DR: Preliminary evidence is reported that denervated adult rat muscle (where sprouting occurs) does contain a factor that permits survival of embryonic motor neurons, similar to that reported by Bennett et a13.
TL;DR: In this paper, it was shown that there were two arcs during the Miocene and Pliocene, a western Northland/Three Kings Rise arc, and an eastern Tonga-Lau/Kermadec-Colville arc.
TL;DR: EHNA + adenosine in a 0.05 mM Ca++ infusion solution conserved ATP, markedly improved the functional recovery of hearts, and thus may have a role to play in myocardial preservation during elective cardiac arrest.
TL;DR: The potential role of antecedent viral infection in the pathogenesis of Type 1 (insulin-dependent) diabetes was investigated by measuring antibody titres to several viruses in serum obtained at the time of diagnosis of diabetes.
Abstract: The potential role of antecedent viral infection in the pathogenesis of Type 1 (insulin-dependent) diabetes was investigated by measuring antibody titres to several viruses in serum obtained at the time of diagnosis of diabetes. An outbreak of Coxsackie B4 infection followed by a wave of Coxsackie B3 and B5 infections occurred in Seattle during the time viral serology was obtained in the diabetic patients. Antibody titres to Cocksackie B5 and Influenza A and B viruses were comparable in diabetics and matched control subjects, but antibody titres to Cocksackie B3 and B4 were lower in the diabetics and a low antibody titre to Coxsackie B3/B4 was associated with a significantly increased relative risk of diabetes.