Showing papers by "University of Canterbury published in 1977"

Secondary sex characters in plants

Abstract: Sexually dimorphic seed plants have partial or complete separation of ovule and pollen functions into two separate sexes, here uniformly called male and female. Secondary sex characters (differences between the sexes in structures other than the androecia and gynoecia) of such populations are reviewed. In a number of perennial species, males exceed females in vigor, growth rate or vegetative reproduction. In several monocarpic or short-lived polycarpic species, including hemp, spinach and species ofSilene, females are larger than males. In asparagus, males exceed females in total growth, but individual shoots of females are larger. In some long-lived species, the greater survival rate of males than of females contributes to a predominance of males, but in species ofSilene andRumex acetosa males have a higher mortality rate than females. Males and females sometimes have different microdistributions, and inMercurialis perennis andRumex acetosella this appears to be associated with different environmental optima of the sexes. Differences between males and females in habit, leaf characters and minor morphological features are described. In a considerable range of species, male inflorescences emerge or bolt earlier and males begin flowering sooner than females. Several authors have suggested that females spend proportionately more of their resources on sexual reproduction (have a higher reproductive effort) than do males. The only available data, those forRumex acetosella, support this. There are more reports of males flowering earlier in life and more frequently, having more numerous inflorescences and more flowers per inflorescence, than of females exceeding males in these features. Differences between individual male and female flowers are reviewed. Secondary sex characters may be incidental consequences of the developmental or genetic basis of sex determination and not adaptive themselves, or they may be selected as optimal strategies for the sexes, or both kinds of explanation may simultaneously be applied. We propose that many of the observed differences between the sexes are of direct selective value in relation to the distinct roles of males and females in sexual reproduction. In particular, the benefits to males of increasing pollen production and to females of increasing ovule production differ in such a way that the optimal reproductive effort will often be less for males than for females; this appears to explain a number of secondary sex characters.

A wind-tunnel investigation of the wind speed and turbulence characteristics close to the ground over various escarpment shapes

Abstract: A wind-tunnel investigation of the wind flow over two-dimensional forward-facing escarpments is reported as part of a continuing research programme into the effects of local topography on the wind flow close to the ground. Four sharp-edged escarpments with their slopes varying between a cliff and a 4:1 gradient, were placed normal to a simulated neutrally-stable rural boundary layer which was modelled to a scale of 1:300. The resulting flows close to the surfaces of the escarpments were measured with a hot-wire anemometer. The modifications to the mean wind speed, turbulence intensity and energy spectra over the escarpments are described. The results indicate the extent and magnitude of the modification to the flow and suggest that significant changes in turbulence characteristics only occur in the wake region close behind the crest, where a shift of energy to higher frequencies is evident.

Rates and forms of erosion on intertidal platforms at Kaikoura Peninsula, South Island, New Zealand

Abstract: Shore platform development and processes are examined for Kaikoura Peninsula on the north-east coast of the South Island, New Zealand. The environment is exposed to high energy storm and swell waves, is mesotidal (mean range 1.36 m, maximum 2.57 m) and has a temperate climate with moderate rainfall (average 865 mm yr-1). Shore platforms range from 40 m to over 200 m wide and are cut in Tertiary mudstones and limestones. Most of the profiles display a prominent low water cliff, an outer rampart and channels developed along lines of structural weakness. The inner margins are extensively mantled in beach, hillslope, and lagoonal sediments which are being rapidly eroded except for three locations where there is an active marine cliff. Net tectonic uplift of the peninsula is thought to be of the order of 108 m during the Quaternary and 2 m during the last 1000 years. The shore platforms are thus clearly polycyclic and contain “inherited” morphological features but are being actively rejuvenated by rem...

Longitudinal Dispersion with Dead Zones

Abstract: The dispersion process for an instantaneous line source of solute in a two-dimensional turbulent shear flow with dead zones is formulated to two differential equations, one for the solute in the flow zones and the other for the solute trapped in the dead zones on the bed. Exchange of material occurs between dead zones and flow. Using the Aris moment transformation these equations are converted to a more tractable system of equations which are solved by numerical methods with the aid of a digital computer for zeroth, first, second, and third moments of the longitudinal concentration distribution. Various forms of dead zone volume are imposed, and its effects on the dispersion process are demonstrated. It is shown for the numerical model employed that dead zones not only increase the rate of dispersion but delay the occurrence of Fickian type dispersion.

Wing loadings, wing shapes, and flight capabilities of procellariiformes

Abstract: Among 48 procellariiform species wing loading increases with increasing body weight. Mean total wing area varies allometrically with mean body weight: log10 wing area (cm2)=20.42 log10 body weight (g)0.588. The power exponent is significantly less than the 0.666 value expected from the law of similitude. Pelecanoides, with wings highly modified for diving, is an exception to the above trend. With increasing size the petrel wing becomes longer and narrower, aspect ratios increasing from about 6.5 in small storm petrels to about 15.6 in the giant albatrosses. Elongation is accompanied by changes in the proportions of the arm bones; the terminal segment, composed of the manus and primary feathers, becomes proportionately smaller and the inner segments, supported by the humerus and radio‐ulna, proportionately larger with increasing body size. Some ecological correlates of interspecific differences in wing loadings and shapes are discussed.

The physiological optics of Dinopis subrufus L. Koch: a fish-lens in a spider.

Abstract: The posterior median eyes of Dinopis subrufus are probably the largest simple eyes found in arthropods, and may reach 1.40 mm in diameter. For a lens 1.325 mm in diameter the focal length is 0.771 mm, giving an F-number of 0.58. This, coupled with the large diameter of the receptors (20 $\mu $m), means that the light absorbed per receptor will be about 2000 times as great as in a diurnal spider such as a salticid, or in the human eye looking at the same extended field. For a lens of this size to produce a resolution of 1.5 degrees - the visual subtense of each receptor - it is shown that spherical aberration has been overcome. This is achieved partly by the lens having a double structure, with an outer region of low refractive index, and a harder core whose apparent refractive index is 1.67. It is argued from the observed resolution of the lens that the core is probably inhomogeneous, like a fish lens, with a central refractive index that could be as low as 1.52. The hemispherical eye-capsule is modified to bring the retina close to the rear surface of the lens, a feature necessitated by the relatively short focal length. The large, hexagonal receptive segments are tightly packed, but there is no tapetum. Some retinal anomalies, the structure of the other eyes of Dinopis, and the relation of its visual optics to its nocturnal habit are also discussed.

Dating of geochemical events in Lake Bonney, Antarctica, and their relation to glacial and climate changes

Abstract: Measurements of major ion concentrations, δ18O, and 14C content of the waters of Lake Bonney have enabled a reinterpretation of the geochemical events which have taken place in the lake and enabled the age of some of these events to be estimated. The sequence appears to have been: (1) Flooding of the Bonney basin with sea water about 100 000-300 000 years ago, some time after the last occupation of the lower Taylor Valley by the Taylor Glacier. (2) Evaporation of the West Lobe to near dryness prior to 15000 years B.P. (3) Penetration of the Bonney basin by meltwaters from the Taylor Glacier, and reflooding of West Lobe by meltwaters derived in part from the glacier, about 15 000 years ago. (4) Reflooding of the East Lobe by meltwaters from the Taylor Glacier as long ago as 5000 years B.P., as a result of the glacier reaching a maximum extension close to its present position. (5) Evaporation of East Lobe to a depth of 19 m perhaps as a result of a temporary retreat of the Taylor Glacier, producing...

Null field approach to scalar diffraction I. General method

Abstract: Invoking the optical extinction theorem (extended boundary condition) the conventional singular integral equation (for the density of reradiating sources existing in the surface of a totally reflecting body scattering monochromatic waves) is transformed into infinite sets of non-singular integral equations, called the null field equations. There is a set corresponding to each separable coordinate system (we say that we are using the 'elliptic', 'spheroidal', etc., null field method when we employ 'elliptic cylindrical', 'spheroidal', etc., coordinates). Each set can be used to compute the scattering from bodies of arbitrary shape, but each set is most appropriate for particular types of body shape, as our computational results confirm. We assert that when the improvements (reported here) are incorporated into it, Waterman's adaptation of the extinction theorem becomes a globally efficient computational approach. Shafai's use of conformal transformation for automatically accomodating singularities of the surface source density is incorporated into the cylindrical null field methods. Our approach permits us to use multipole expansions in a computationally convenient manner, for arbitrary numbers of separated, interacting bodies of arbitrary shape. We present examples of computed surface source densities induced on pairs of elliptical and square cylinders.

Closure to “Tests on Slab-Column Connections with Shear and Unbalanced Flexure”

Abstract: Tests were conducted on eight 1/2-scale models of reinforced concrete interior flat plate-column connections transferring shear and unbalanced moment from gravity and simulated seismic loading. The slab at the connection contained either no shear reinforcement or shear reinforcement in the form of either cranked bars, structural steel shearhead or closed vertical stirrups. The simulated seismic loading was statically applied, either monotonically or cyclically in the inelastic range. The strength and ductility of the connections, and the modes of failure, were compared. The connections without shear reinforcement failed suddenly in diagonal tension. The use of cranked bars as shear reinforcement increased the strength of the connection but did not increase the ductility. The use of a structural steel shearhead resulted in an increase in strength and in a limited increase in ductility. The use of closed vertical stirrups around the slab bars, which passed through the column, resulted in an increase in the strength and in a substantial increase in the ductility of the connection.

Integration of h.v.d.c. links with fast-decoupled load-flow solutions

Abstract: A model of the high-voltage direct-current transmission link suitable for incorporation in fast decoupled a.c. load-flow programs is described. The model is not restricted to a particular control made and provision is made to alter the control equations according to prespecified constraints for the variables. The versatility of decoupled programs is increased with this addition and it is shown that their reliability and computational efficiency are maintained.

Effects of the haematophagous mite Ornithonyssus bursa on nestling starlings in New Zealand

Abstract: The breeding of starlings (Sturnus vulgaris L.) in 160 nest boxes in the Manawatu region during 1974–75 and 1975–76 is described. Ornithonyssus bursa, a mesostigmatic dermanyssid mite with a 5‐stage life cycle, is a continuous parasite of several species of birds, including the starling. The seasonal pattern of O. bursa infestation over the starling breeding season is described with particular emphasis on the proportion of nest sites infested and the degree of infestation in early, middle, and late periods of the breeding season. Mites had no demonstrable major effects on the growth rate, weight at 15 days, mortality, blood characteristics, and lipid stores of starling nestlings. A pair of starlings can raise 3 or 4 nestlings, whether mite‐infested or not, with no significant difference between nestling weights at age 15 days. A heavy mite load of 50 000 in a nest box with 4 nestlings is calculated to take 3.5 % by weight of the blood of each nestling per day, a loss which healthy nestlings can apparently...

A technique for obtaining clean cut surfaces on wood samples prepared for the scanning electron microscope

Abstract: SUMMARY A technique is described for obtaining clean cut surfaces on wood samples prepared for the scanning-electron microscope.

Saturated platelets are new intermediates in hydrocarbon pyrolysis and carbon formation

Abstract: Formation of solid carbon during pyrolysis of gaseous hydrocarbons may involve ‘saturated platelet’ intermediates.

An interactive aid for musicians

Abstract: An interactive aid for musicians is described, together with its applications to music teaching, music composition, real-time performance and music typesetting. The system permits the input of sounded music and its subsequent playback using an electronic organ. Facilities for transcription, display and editing are provided using a graphical display unit. A digital synthesizer is incorporated for sophisticated sound generation. Problems encountered with transcription, display and editing of sounded music are identified. A performance-oriented music notation is described, and compared with conventional music notation. The requirements of both notations are assessed with respect to the transcription, display and editing tasks. The value of an interactive rather than fully automatic system is emphasized. Software and data-base organization of a transcription system permitting the display and editing of both notations is described. Results are presented of practical uses of the system.

Ovular Morphology and the Classification of Dicotyledons

Abstract: Four types of ovule are defined by integument number and nucellar thickness Their distribution throughout the dicotyledons is summarized and their importance in defining major subclasses is advocated In particular, those families with ovules having a single integument are considered to form a complex of orders and families which includes most sympetalous and several polypetalous groups (including Cornales, Araliales, Escalloniaceae and Pittosporaceae) This complex (provisionally referred to as the Unitegminae) is believed to comprise the modern representative of a distinct evolutionary line within the dicotyledons

Growth eccentricity and reaction anatomy in branchwood of Drimys winteri and five native New Zealand trees

Abstract: Growth eccentricity and reaction anatomy in horizontal or inclined branches of Drimys winteri J.R. et G. Forst. and five native New Zealand tree species are described. The species investigated show characteristic distribution patterns of growth eccentricity along the branch length. Anatomical differences between wood from the lower and upper sides of inclined branches occur in all six species investigated. Compression wood is a regular feature in Phyllocladus alpinus Hook. f.; as is tension wood in Nothofagus solandri var. cliffortioides (Hook. f.) Poole. Myoporum laetum Forst. f., Myrsine australis (A. Rich.) Allan, Pennantia corymbosa J.R. et G. Forst., and Drimys winteri develop neither compression wood nor tension wood.

Diverging Type-D Metrics

Abstract: This paper contains an investigation of algebraically special spaces with two commuting Killing vectors. It is shown that the field equations for these spaces can be reduced to two ordinary differential equations, one of which is quasi-linear in one of the variables. The metric is type D iff it possesses a two dimensional, abelian, orthogonally transitive symmetry group. Finally, the type D metrics of Kinnersley are expressed in various coordinates, including those of Plebanski and Demianski.

The clypeal glands of Mynoglenes and of some other linyphiid spiders

Abstract: The clypeal glands of three New Zealand Linyphiidae currently placed in Mynoglenes are described, by light, scanning and transmission electron microscopy. Shallow sulci beneath the lateral eyes of both sexes trap secretions which are produced by greatly elongated cells packed radially with respect to a given sulcus, and each voiding its product to the exterior by an individual ductule. The function of the secretion is unknown, although the ultrastructure of the gland resembles that of the defensive glands of many insects, but there is no separate duct cell, and the basal region of each secretory cell exhibits a unique strategy of membrane amplification, which divides the cytoplasm longitudinally into compartments by folds of the plasma membrane, compartments being still further subdivided into “tails”. Patterns of vacuolation observed in various regions of the cytoplasm support the hypothesis that these unusual structures may be concerned with rapid water transport from the haemocoele, and that the cells discharge their contents by a “flush-out” mechanism. It is shown that male Erigoninae with cephalic specializations have similar clypeal glands, but with cytological profiles (in alcohol-fixed material) which suggest that special forms of membrane amplification are not present. Glands are absent in female Erigoninae, and in males with unmodified heads. It is suggested that in this latter subfamily the cephalic modifications may serve as presenting surfaces for sexual pheromones.

Bedload transport by translation waves

Abstract: The response of a gravel bed reach to imposed steady flows and to gradually varying triangular translation waves is examined, firstly, under equilibrium transport conditions and, secondly, with no bedload inflow. With equilibrium transport no significant differences could be found between the sediment hydrograph associated with the wave and the comparable steady state sediment hydrograph. This result, combined with the observed but small variation in resistance implies that the use of steady state resistance and bedload formulae in a mathematical model of the situation can be justified. With nonequilibrium transport differences occurred between measured nonsteady sediment hydrographs and the comparable steady hydrographs due to a bed response effect. This diminished towards the downstream end of the scour region associated with a wave's passage. Consequently mathematical model performance would be poor when the reach length is less than the scour hole length. /Author/

Computer-analyzed measures of characteristics of human locomotion and mobility

Abstract: Path and speed characteristics of human locomotion were detected by a mechanical sensing system and processed by a digital computer to give graphical and numerical measures of performance. The problems of deriving such indices are discussed, and a number of simple experiments are included to demonstrate that these measures yield dependent variables suitable for use in the study of the perceptual information required for mobility and locomotor control.