Showing papers by "University of Newcastle published in 1970"

Development, Fecundity and Brooding Behaviour of the Amphipod, Marinogammarus Obtusatus

Abstract: Marinogammarus obtusatus Dahl, an intertidal amphipod, was first described by Dahl (1938). Prior to this date it appears that this species was often confused with and identified as M. marinus. In later years, M. obtusatus has been shown to be common around the coast of Britain (Sexton & Spooner, 1940), and in a preliminary survey of Cullercoats Bay, Northumberland, we have found that this species is by far the commonest amphipod present.

A Study of validity of open‐field measures

Abstract: Seven open-field measures (defecation, ambulation, urination, washing, rearing, latency and inner circle activity) were obtained using a number of different scoring methods for albino and hooded rats. The validity of these measures was examined using (a) day by day decrease of open-field behaviour, (b) effects of retesting over a period of time, (c) variation of stimulus intensity (light and noise). It was found that methods a and b did not provide satisfactory validity estimates. Method c indicated that defecation and latency can be accepted as valid indices of emotionality in rats.

Weak Ion-Acoustic Shock Waves

Abstract: Weak nonlinear ion-acoustic waves in a plasma consisting of cold ions and warm electrons are investigated by using a nonlinear perturbation method. In the lowest order of perturbation, it is found that the system of equations for the ion-acoustic waves can be reduced to the following single nonlinear dispersive-dissipative equation: \begin{aligned} \frac{\partial u}{\partial\tau}+u\frac{\partial u}{\partial\xi}+\mu\frac{\partial^{3}u}{\partial\xi^{3}}- u\frac{\partial}{\partial\xi}\left(\frac{\partial u}{\partial\tau}+u\frac{\partial u}{\partial\xi}\right){=}0, \end{aligned} where u , ξ and τ are normalized velocity of ion-fluid, stretched space and time coordinates, respectively. The parameter µ is a measure of dispersion due to charge separation, whereas ν is a measure of dissipation due to electron-ion collisions. It is shown that this equation has either oscillatory (dispersion-dominant case) or quasi-monotone (dissipation-dominant case) shock wave solutions.

Variable relationships in central place and retail potential models

Abstract: Davies R. L. (1970) Variable relationships in central place and retail potential models, Reg. Studies 4, 49–61. Considerable efforts have been spent by geographers and planners to find suitable measures of the concepts of centrality and attractiveness in shopping models. Numerous indices have been advocated which emphasize the functional and qualitative aspects of shopping centres, but these vary in nature and scope and are often dependent on field surveys or special computations. From examination of three case-study areas, it is shown that such indices are not necessarily in any more agreement with each other in hierarchic rank placements of shopping centres than they are with rankings assigned by more general variables of census statistics. It is questioned whether their applicability to shopping studies in a practical context is any greater than use of certain more commonly available and compatible census data.

Spectral factorization of time-varying covariance functions: The singular case

Abstract: If a known linear system is excited by Gaussian white noise, the calculation of the output covariance of the system is relatively straightforward. This paper considers the harder converse problem, that of passing from a known covariance to a system which will generate it. The problem is solved for covariancesR y (t, τ) with |R y (t, t)| < ∞ for allt and such that they-process is Gauss-Markov, i.e., it may be obtained as the output of a linear finite-dimensional system excited by white noise.

Scattering matrix synthesis via reactance extraction

Abstract: This paper considers the problem of multiport passive network synthesis for a rational bounded real scattering matrix S(p) using state-space ideas The technique is to extract reactances from a network synthesizing the prescribed S(p) to yield a resistive coupling network that may contain transformers, resistors, and if there is no reciprocity constraint, gyrators Here a minimum number of reactive elements are always sufficient to give a synthesis, reciprocal and nonreciprocal The synthesis method relies on an algebraic criterion for a class of rational matrices termed "discrete bounded real" that solves the passive synthesis problem Starting with an arbitrary coordinate basis, a state-space description is found for a discrete bounded real matrix derived from the given bounded real S(p) A coordinate transformation of the state-space is found from the solution of an algebraic equation, which yields almost immediately a passive synthesis for S(p) When a synthesis for a symmetric bounded real S(p) is required to use no gyrators, a further state-space, basis transformation is found that preserves passivity and simultaneously inserts reciprocity The contributions of this paper, to scattering matrix synthesis, are twofold: first, to solve the nonreciprocal synthesis problem including the mimimal reactive element equivalence problem via calculations that need not rely on application of any classical ideas, and second, to present for the first time a reciprocal synthesis of a passive symmetric scattering matrix with a minimum number of reactances using state-space ideas

Youth in Australia: A Survey of Background and Problems

Abstract: THE IMAGE which Australia has presented to the world is that of a vast, empty, sunburnt country, with an oddly distinctive fauna and peopled with ruggedly independent pioneers who raise wheat and sheep, and combat drought, flood, and fire for survival. It is of a country which produces more than its share of athletes, tennis players, and swimmers in times of peace, and hard-fighting soldiers in wartime. Such

Interlacing methods and large indecomposables

Abstract: The method of interlacing of modules, like amalgamation of groups, is a way of getting new objects from old. Briefly, the interlacing module we consider is a certain factor module of a direct sum of copies (finite or infinite) of an original module M . The conditions given in a previous paper by the first author in order that the interlacing module (using finitely many copies) be indecomposable are here greatly weakened, and we further allow the number of copies of the original to be infinite. R. Colby has shown that if R is a left artinian ring, the existence of a bound on the number of generators required for any indecomposable finitely-generated left R -module implies that R has a distributive lattice of two-sided ideals. This result is extended to rings whose identity is a sum of orthogonal local idempotents. For these rings the same distributivity is proved in case every indecomposable interlacing module of the above type which begins with an indecomposable projective M is finitely-generated. A consequence is that any finite-dimensional algebra over a field having infinitely many two-sided ideals has infinite-dimensional indecomposables.

ΔΙΑΝΟΙΑ and Plato's Cave

Abstract: In Part I of his paper Cooper gives indisputable evidence regarding Plato's use of the man-made image as a step to the apprehension of a Form under discussion, whether that image be in fact a diagram or a model, or simply a verbal picture, such as his imaginative account of Justice within a community, which we find used to provide us with in Republic 443 c 4 ff. However, Cooper goes on to assure us that the divided-line figure offers us only three types of object: ‘We have three kinds of objects which differ from one another in clearness and esteem, firstly, the Forms, secondly, the objects of ordinary sense-perception, and thirdly, images, shadows and reflections.’ Now the admitted fact that, as he notes, Republic 10 (597 b 5-e 5) gives the same three orders of reality, does not entirely absolve Cooper from all the implications of Plato's decision to divide his line into four parts rather than three; for it is made quite clear in 509 b 6–10 that the Form of the Good, is the source of being as well as of knowledge, so the Line must also classify both.

Identity of sporopollenins with older kerogens questioned.

Abstract: THE most commonly used definition of kerogen is that of Forsman1: “the insoluble organic matter occurring in sedimentary rocks”. Thus, kerogen includes a range of composition from coaly material to the insoluble organic matter of oil shales. Kerogen may be amorphous or may indicate a biological origin.

A note on feedback compensators in optimal linear systems

Abstract: Two basic methods for designing feedback compensators which may be used to achieve arbitrary closed-loop pole positions are now available. This correspondence shows that when each method is used within the framework of optimal control the same compensator structure results, but the more standard approach using a state estimator and a linear law appears to be the more attractive from the information now available.

Precarious Employment in the New Zealand Call Centre Industry

Abstract: Precarious employment is an increasingly prevalent phenomenon in contemporary labour markets. Research on the call centre industry has not only identified a growing use of non-standard employment arrangements, but also evidence to indicate that precariousness may be a feature of employment in this industry. Despite this evidence, however. There is still little known about the extent to which precarious employment is an integral part of the NZ call centre context. In addition, there has been scant research on the individual experiences of non-standard workers employed in the call centre industry. This paper aims to address the gaps in the literature by essentially 'marrying' these three broad areas of research. A framework for measuring precariousness is introduced and examined in relation to two case study call centres, selected to facilitate a comparative approach. Based on in-depth interviews with case study participants and key stakeholders, this paper examines the applicability of this framework to the NZ call centre context. Key findings from the study indicate that precarious employment is indeed a phenomenon that affects non-standard workers in the NZ call centre industry. A number of policy concerns are raised through the data, particularly where the incidence of precarious employment is associated with the lack of organisational compliance with employment legislation.

Detection of Weak Light Signals

Abstract: The experimental signal-to-noise ratios (S/N) of four photomultiplier light-detection systems are obtained for two values of the dc anode signal and dc anode dark current. The photodetection systems investigated are dc amplifier, lock-in, noise power, and combined lock-in plus noise power. Although there is no significant difference between the experimental S/N ratios of the noise power and lock-in-plus-noise-power system, they both produce significantly greater S/N ratios than the other methods. Theoretical S/N ratios are calculated assuming that shot noise only is present, and are compared with the corresponding experimental values.

A classification learning set which is a possible model for conservation of quantity

Abstract: Conservation of quantity was analysed as a classification task. Quantities were classified according to height and breadth into a 2-dimensional classificatory system. This system corresponds to the operation of logical multiplication of heights and breadths. It is also a system in which all Ss' judgments, perceptual and cognitive, are brought into consistent relationships with one another. The system was taught by training Ss to recognise correspondences between equivalent categories of quantities in different sets of material. Learning set training consisting of 14 problems over 7 sessions was given to pre-school children, to nonconservation children over 5 years and to conservation children. All subjects over 5 years showed improvement over problems. Pre-school subjects did not. The experiment is interpreted as showing that pre-school children cannot contruct the logical basis of conservation, whereas children over 5 show some ability to do so.

The teacher's therapeutic role in ordinary classroom situations

Abstract: In the class-room, the teacher has two roles, to teach academic content and to teach therapeutically. It is not a question of whether or not the teacher should engage in psychotherapy. He cannot avoid some relationship with it. Aspects of the relationship are documented. Limitations upon this aspect of the teacher's role are considered. His advantages include the availability of certain knowledge and techniques from various therapeutic approaches, and certain diagnostic and treatment factors. The teacher is seen in a unique position where, with adequate training, he can make valuable contributions to psychotherapy and mental health in the community.

Vibrotactile Learning and the Locus Dimension

Abstract: Forty subjects, each of whom was randomly allocated to one of four experimental groups, learned a 26-element vibrotactile code. Each group used either 3, 4, 5 or 6 vibrators. As predicted, the performance of each group improved in the order 3−, 4−, 5− and 6−vibrators. Although there were no significant differences between the groups there was a highly significant learning effect over ten trials. Error analyses showed that duration errors were the most frequent type of error and that intensity errors were the least frequent. It is suggested that both the types of errors and the optimum number of loci which can be separately stimulated in this type of experiment will depend upon the spacing and arrangement of signal elements.

Family planning in the pacific islands: The Fijian example

Abstract: Fiji which adopted family planning as official policy in 1962 has had a highly successful family planning program. Administered by the Medical Department free clinic services and subsidized contraception ar e available throughout the island. By 1968 18053 women out of 108847 women of child-bearing age were using some kind of contraceptive. Part of the success of the program must be attributed to the Fijan Family Planning Association which is responsible for motivational activities and operates 16 centers. There has been a dramatic decline in the birthrate from 40/1000 in 1960 to 30/1000 in 1968. Most of the decline has been due to a steep decline in the birthrate among the Indian population of Fiji. The Indian population shows a trend for marrying at later ages and for postponing pregnancy. The Fijians who number 214948 out of the total population of 512062 have not responded strongly to family planning programs. Until 1968 the Fijian birthrate was maintained at about 37/1000. There is evidence however that Fijians may utilize family planning methods with more frequency in the near future.

A quadratic performance index maximization problem

Abstract: The problem is considered of maximizing a positive quadratic functional of the states of a linear system, subject to a bound on the integral of the square of the control. The solution is characterized in terms of the maximum eigenvalue and associated eigenfunction of a non-negative, definite, self-adjoint, integral kernel, and computational techniques for solving the associated eigenvalue problem are discussed.