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Showing papers by "Queen's University published in 1981"


Journal ArticleDOI
TL;DR: It is concluded that the atrial extract contained an extremely powerful inhibitor of renal tubular NaCl re absorption, which caused a rapid, more than 30-fold increase of sodium and chloride excretions, while urine volume and potassium excretion doubled.

3,051 citations


Journal ArticleDOI
TL;DR: In this article, it is shown that there are reasons to expect two-way trade even in identical products, due to strategic interaction among firms, and that such trade arises because slightly different commodities are produced and traded to satisfy consumer's tastes for variety.

816 citations


Journal ArticleDOI
TL;DR: On analysis ofin vitro assays of human natural killer (NK) cell function the inadequacy of commonly used methods of expressing lytic activity was apparent and a comparison was made of the data obtained using modifications of two equations—the simple exponential fit and the von Krogh equations.
Abstract: On analysis ofin vitro assays of human natural killer (NK) cell function the inadequacy of commonly used methods of expressing lytic activity was apparent. A comparison was made of the data obtained using modifications of two equations—the simple exponential fit and the von Krogh equations. Both of these equations were found to satisfy the following essential criteria for use in these assays. First, the majority of the results obtained in the chromium-release assay could be used in data reduction; second, the resultant “dose-response” curve was reduced to linearity; and third, a single numerical expression was obtained which was directly proportional to the cytotoxic activity. Of the two methods the more conventional exponential fit was found to be the simpler to use. The closeness of fit of the experimentally derived data to the ideal curves did not support the possibility that normal lymphocyte preparations contain suppressor cells capable of inhibiting NK activity. Data have also been presented showing that NK-sensitive targets could be categorized with respect to their susceptibility by comparing the slopes of the target cell survival curves obtained using the exponential fit equation. These observations are relevant to the accurate assessment of NK activity in patient populations and to the determination of the effects of disease and its treatment on this activity.

681 citations


Journal ArticleDOI
TL;DR: In this article, the authors synthesize various procedures for testing non-nested hypotheses within the framework of artificial nesting, and establish the result that different tests correspond to different treatments of its identification problem.

235 citations


Journal ArticleDOI
01 May 1981-Nature
TL;DR: A general equation for differential change in fitness is presented which exhibits the equilibrium sex ratio as achieving a balance between the factor contained in Fisher's standard grandchild argument and a second factor resulting from intra-sex sibling interactions over reproductive resources.
Abstract: Fisher1 produced the first general argument that a random-mating sexually-reproducing population should devote equal reproductive resources to the production of male and female offspring, while Hamilton2 considered several unusual situations in which the expenditure of reproductive resources should be biased towards one sex or the other. His ‘host’ model has been widely cited3–6 and at least three factors proposed as the cause of the sex ratio bias: local mate competition, sib-mating and inbreeding. The problem of which of these factors is the real cause of the biased sex ratio seems important in view of the large number of apparently different but often closely related sex ratio models which are now being proposed. It would be useful to have ways of classifying them according to the presence of different factors which affect the equilibrium sex ratio. Here, I present a general equation (equation (2)) for differential change in fitness which exhibits the equilibrium sex ratio as achieving a balance between the factor contained in Fisher's standard grandchild argument1 and a second factor resulting from intra-sex sibling interactions over reproductive resources. In particular, I analyse Hamilton's host model2 for the presence of these different factors.

205 citations


Journal ArticleDOI
TL;DR: The conceptual framework emphasizes the application of musical rules as an illustration of rules governing auditory sequences in general as well as the abstraction and analysis of levels of pitch relations conducted even by musically untrained listeners.
Abstract: Three experiments studied the perception of tone sequences having various degrees of musical structure. Ratings of perceived structure and ease of recognition in transposition were both influenced by harmonic progression (as defined by music theory), the contour (directional changes in pitch), and the excursion or repetition pattern within the sequence. The relation between the original and transposed sequence also affected ease of recognition in accordance with the number of tones shared between the two sequences. The results are described in terms of the abstraction and analysis of levels of pitch relations, an analysis conducted even by musically untrained listeners. The conceptual framework emphasizes the application of musical rules as an illustration of rules governing auditory sequences in general.

194 citations


Journal ArticleDOI
08 May 1981-Science
TL;DR: A sexual dimorphism in the functional asymmetry of the damaged human brain is reflected in a test-specific laterality effect in male but not in female patients, which explains some contradictions concerning the effects of unilateral brain damage on intelligence in studies in which the influence of sex was overlooked.
Abstract: A sexual dimorphism in the functional asymmetry of the damaged human brain is reflected in a test-specific laterality effect in male but not in female patients. This sex difference explains some contradictions concerning the effects of unilateral brain damage on intelligence in studies in which the influence of sex was overlooked.

191 citations


Journal ArticleDOI
TL;DR: The results indicate that the bar-probe task cannot be explained in terms of a simple iconic memory concept, and requires a feature buffer, an “intelligent” letter identification process, and a postidentification character buffer.
Abstract: The partial report tachistoscopic task has been used to define “iconic memory,” a labile image-like precategorical visual store. Six interrelated partial report studies are reported that challenge the construct. On each trial, subjects were shown an eight-letter pseudoword (representing one of four orders of approximation to English) and a bar probe indicating which letter to report. The probe was delayed systematically, and the experiments included both mask and no-mask conditions. All three variables-familiarity of the material, masking, and delay of the probe-affected accuracy of report. Delaying the probe, for example, reduced accuracy by increasing location errors. Delaying the mask increased accuracy by reducing both location and item errors, but it did not reduce the location errors until its effect on item errors had reached asymptote. Across the stimulus array, however, masking reduced accuracy at all delays by increasing location errors. Finally, the greater accuracy associated with higher orders of approximation to English was complemented by a decrease in item errors, but the familiarity factor had no effect on location errors. Taken together, even though the task has been used to define the idea, the results indicate that the bar-probe task cannot be explained in terms of a simple iconic memory concept. Instead of a simple image-like buffer, the explanation requires a feature buffer, an “intelligent” letter identification process, and a postidentification character buffer. Iconic memory is a construct that oversimplifies the information processing system used in the bar-probe task.

186 citations


Journal ArticleDOI
TL;DR: The authors found that the perceived magnitude of surface roughness and the consistency of such judgments were identical under the two modes of tactual examination under both active and passive touch with object movement.
Abstract: Subjects made magnitude estimates of the roughness of metal gratings by both active and passive touch (with object movement). The perceived magnitude of surface roughness and the consistency of such judgments were identical under the two modes of tactual examination. The results have implications for sensory physiology studies of the cutaneous peripheral mechanisms that underlie texture. They also question the prevailing notion in somethesis and tactual perception that active touch is always superior to passive touch.

186 citations


Book ChapterDOI
01 Jan 1981

162 citations


Journal ArticleDOI
John Olson1
TL;DR: In this paper, the way teachers used the materials of a particular innovation, the Schools Council Integrated Science Project, is described and explained in terms of teacher control over the uncertainties of classroom life.
Abstract: Innovative doctrines create dilemmas for teachers. These dilemmas arise because, when teachers decide to adopt new practices, they face new uncertainties about their role in the classroom, the effectiveness of their methods and the purposes of their instruction. The way teachers used the materials of a particular innovation, the Schools Council Integrated Science Project, is described and explained in terms of teacher control over the uncertainties of classroom life. The Project proposals, initially seen by teachers as increasing the diffuseness of their work, were modified by them so that it was clearer to them what was to be accomplished and how it was to be done. At the same time, a functional alignment of goals, techniques and social relationships was maintained through teacher influence in the classroom. The translation of the materials into more specific terms meant that important elements of the “doctrine” of the Project were either ignored or redefined in more traditional terms. Such redefinition of innovation in specific terms raises questions about the effectiveness, as instruments of change, of centralized curriculum projects remote from the practical problems of schools. Implications for curriculum policy and research into the dilemmas teachers face in teaching are discussed.

Journal ArticleDOI
TL;DR: The name Lipophorin is proposed as a generic term for the class of insect haemolymph lipoproteins that serve to transport lipids between organs of absorption, storage and utilisation.

Journal ArticleDOI
TL;DR: The comparability of the two senses in texture-related tasks may underlie the relatively equal compromise between discrepant sources of texture information demonstrated in Experiment (modality superiority interpretation).
Abstract: Three experiments were performed involving the perception of surface texture. Experiment 1 indicated that when vision and touch are presented with discrepant information concerning texture, the two senses appear to weight the information about equally. Moreover, Experiment 2 showed that using touch, vision, or touch and vision, subjects performed a texture identification task with comparable matching accuracy and precision. Experiment 3 demonstrated that using the same three modes, subjects performed a magnitude estimation task similarly, in terms of magnitude estimates of roughness, the rates of growth of perceived roughness, and response precision. The comparability of the two senses in texture-related tasks may underlie the relatively equal compromise between discrepant sources of texture information demonstrated in Experiment (modality superiority interpretation). Such a compromise is somewhat different from that commonly reported in the sensory conflict literature. The relative weighting of multiple sources of sensory information about surface texture was also considered in terms of a directed-attention interpretation of intersensory organization.

Journal ArticleDOI
TL;DR: The results showed unequivocally that the long-lasting muscle weakness which arises from box-stepping was due to the negative component of the work and suggested repeated stretching of the triceps surae muscles during the eccentric phase of work in the “negative” leg may cause actual muscle damage.
Abstract: The separate effects of negative (eccentric) and positive (concentric) work on stimulated and voluntary isometric contraction of the triceps surae were studied in five healthy male subjects following the performance of boxstepping for 1 h with a constant leg lead. The results showed unequivocally that the long-lasting muscle weakness which arises from box-stepping was due to the negative component of the work. The maximal twitch ( $$P_{ t_{_0 } } $$ ) and tetanic (P 0) tensions at 10, 20, 50 and 100 Hz were markedly reduced in the leading (“negative”) leg, which was constantly required to absorb the force of body weight as the subject returned from box to floor, whereas the trailing (“positive”) leg which lifted body weight from floor to box was relatively unaffected. The decreases in $$P_{ t_{_0 } } $$ andP 0 at 20 Hz in the “negative” leg following work were 38 N and 765 N (25% and 55%) respectively and recovery was slow (>20 h). A 2 min “fatigue” test reflected the changes inP 0; a reduction of absolute force was only seen in the negative leg though the relative (%) decline in tension was the same in both legs and its rate did not differ significantly following exercise from control conditions, which suggests the muscles were weaker but not more fatiguable following exercise. At submaximal voltages of stimulation muscle tensions at 20 and 50 Hz were enhanced in the “positive” leg but depressed in the “negative” leg, the relative (but not absolute) loss of force being greater at 20 Hz than 50 Hz which gave rise to long-lasting fall in the 20/50 tension ratio. The loss of high frequency (50 Hz) force was associated with changes in MVC: MVC (N)=507+0.937P 0 (N);r=+0.846. It was suggested that repeated stretching of the triceps surae muscles during the eccentric phase of work in the “negative” leg could affect the efficacy of the contractile machinery directly and may cause actual muscle damage. The subjects complained of muscle soreness for 5–7 days after the experiments.

Journal ArticleDOI
TL;DR: In the absence of acid the released mucus was stabilized by a network of fibrin, and epithelial continuity was reestablished over non-hyperemic regions by migration of epithelial cells from the gastric pits.
Abstract: This study was undertaken to differentiate between the morphological changes produced in chambered rat gastric mucosae by 40% ethanol and by 50 mM HCl. 40% ethanol produced both focal mucosal hyperemia and widespread exfoliation of the surface epithelium. Massive release of mucus accompanied both events. In the absence of acid the released mucus was stabilized by a network of fibrin, and epithelial continuity was reestablished over non-hyperemic regions by migration of epithelial (and parietal) cells from the gastric pits. Hemorrhagic erosions occurred only in the presence of acid, but were limited to the hyperemic regions. Acid had the following effects: (1) platelet thrombi were destroyed, thus promoting hemorrhage; (2) destruction of the fibrin network by acid caused dissipation of the adherent mucous coat; (3) vulnerable cells which had previously shown only ischemic damage were irreversibly damaged by acid; (4) exposed basal lamina was destroyed, thus removing the substratum necessary for orderly epithelial re-establishment.

Journal ArticleDOI
TL;DR: In this paper, the effect of acute ingestion of ethanol on small intestinal functions was examined in detail and the mechanism(s) of action of a single dose of alcohol was defined.
Abstract: There is evidence to indicate that chronic alcoholism may lead to steatorrhea, malnutrition, or simple diarrhea (1). These conditions may arise from impaired intestinal function, from abnormal pancreatic and hepatobiliary secretion, or from a combination of all the above (2). Because of this, it is important to dissect the effects of alcohol on the small intestine from those on other organs. Wilson and Hoyumpa (3) reviewed, in general, the effect of acute and chronic intake of alcohol on intestinal transport processes. However, before one can even hope to understand the effect of chronic alcohol intake on small intestinal function, it is necessary to define the mechanism(s) of action of a single dose of alcohol. Accordingly, in this review, we have examined in detail the effect of acute ingestion of ethanol on small intestinal functions.* To focus on this subject adequately, studies on the effect of chronic ethanol intake are not included.


Journal ArticleDOI
TL;DR: There was a marked reduction in bladder compliance with a striking rise in baseline bladder pressure during bladder filling, and hyperreflexia with involuntary contractions of the detrusor muscle at low bladder capacity after Wertheim hysterectomy.

Journal ArticleDOI
TL;DR: The results show for the first time that in demyelinating disease, a “dying‐back” process similar to that described in axonal disease can affect the oligodendrocyte.
Abstract: Recurrent demyelination was produced in mice by Cuprizone administration. During the second course of Cuprizone, the animals showed greater resistance to the toxin and demyelination occurred slowly and was complete only after prolonged periods. The earliest changes in oligodendrocytes occurred in the most distal processes, the inner cytoplasmic tongues, which showed degenerative changes 3 to 4 weeks before degeneration of the oligodendrocyte cell bodies or demyelination occurred. The results show for the first time that in demyelinating disease, a "dying-back" process similar to that described in axonal disease can affect the oligodendrocyte.

Journal ArticleDOI
TL;DR: In this article, if state and local governments maximize their residents' welfare, and cannot distinguish between individual residents and non-residents but know the aggregate characteristics of the two groups, what set of taxes (subsidies) and public goods should they choose?


Journal ArticleDOI
TL;DR: Investigation of the response characteristics of single cells in the nucleus of the basal optic root of the accessory optic system of pigeons suggest that this nucleus may be involved in processing self-induced visual motion information required for vertical optokinetic stabilization.
Abstract: This study investigated the response characteristics of single cells in the nucleus of the basal optic root (nBOR) of the accessory optic system of pigeons. One hundred and twenty-one nBOR cells were studied and quantitative data from 87 units indicated that they preferred very large random patterned stimuli, and did not respond to stimuli less than 30 ° in diameter. In many cases the receptive field encompassed the entire monocular visual field. nBOR cells were directionally sensitive with approximately 70% preferring motion with an upward vector. They responded to very slow velocities in the range of 0.5 ° to 5.0 ° s−1, and did not adapt to continuous stimulation. Maximal responses occurred to very large randomly patterned stimuli moving slowly in an upward direction. These response characteristics together with the anatomical connections of the nBOR suggest that this nucleus may be involved in processing self-induced visual motion information required for vertical optokinetic stabilization.

Journal ArticleDOI
TL;DR: These neurons seem well suited to respond to local (object) motion and to ignore translation of the visual image arising from body, head and eye movements, suggesting a double opponent-process directionally specific receptive field organization.
Abstract: The experiments reported in this paper were carried out to determine the effect moving background patterns have on the response characteristics of directionally specific neurons in the pigeon optic tectum First, care was taken to select the optimal single stimulus for each cell, then large textured patterns were added to the test stimulus and moved either ‘in-phase’ or ‘anti-phase’ Altogether 214 cells were studied in 77 white Carneaux pigeons and it was found that all cells below a depth of 400 microns were inhibited by backgrounds moved ‘in-phase’ with the optimal test stimulus, while few cells above this level were affected in any way by backgrounds All directions of background motion containing an ‘in-phase’ vector resulted in rather profound inhibition of the directional response while directions with an ‘anti-phase’ vector produced less inhibition and sometimes were even facilitated by direct ‘anti-phase’ The velocity tuning curves obtained with an optimal single test stimulus and by ‘anti-phase’ movement of backgrounds were essentially similar


Journal ArticleDOI
J. Lodge1, M. Fahmy
TL;DR: In this article, it was shown that for any 2D digital filter satisfying Shanks' criterion there exists a realization that cannot support overflow oscillations, and a technique for determining whether a normal realization exists for a given 2D discrete system.
Abstract: An important theorem relating to the Lyapunov stability of two-dimensional discrete systems is proven. Using this theorem it is shown that for any 2-D digital filter satisfying Shanks' criterion there exists a realization that cannot support overflow oscillations. In the process of proving the theorem some interesting results on the multi-dimensional bilinear transformation are developed. One of these results yields a simple test that can be used to check the stability of a 2-D discrete transfer function that has been obtained from the bilinear transform of a 2-D continuous transfer function with a 2-D Hurwitzian denominator polynomial. A technique is given for determining whether a normal realization exists for a given 2-D discrete system. Also, a theorem is presented that allows the determination of the norm of the minimum norm realization of a given transfer function. A noniterative technique for obtaining a low norm realization and an iterative technique for obtaining a minimum norm realization are developed.

Journal ArticleDOI
TL;DR: In this note the class of functions which can appear as outputs is identified for a class of multivariable nonlinear systems and right-inverse systems which act as prefilters are constructed.
Abstract: In this note the class of functions which can appear as outputs is identified for a class of multivariable nonlinear systems. For these systems we construct right-inverse systems which act as prefilters.

Journal ArticleDOI
P. K. Rose1
TL;DR: The three‐dimensional distribution of dendrites from the dorsal neck muscles biventer cervicis and complexus was examined in the adult cat using intracellular staining techniques and followed an orderly pattern.
Abstract: The three-dimensional distribution of dendrites from the dorsal neck muscles biventer cervicis (BC) and complexus (CM) was examined in the adult cat using intracellular staining techniques. Motoneurons were electrophysiologically identified, stained with injection of horseradish peroxidase, and reconstructed from serial histological sections. The dendritic distributions of all motoneurons examined followed an orderly pattern. Many dendrites extended rostrally and caudally to form of complex parallel collection of dendrites in the ventromedial nucleus. Other dendrites projected dorsolaterally into the spinal accessory nucleus and lateral parts of lamina VII and VIII. Dorsomedial dendrites followed a path parallel to the medial border of the ventral horn are frequently terminated near the central canal. A new scattered dendrites were usually found directly dorsal to the soma in lamina VIII. This pattern of dendritic distribution differed distinctly from the dendritic distribution of motoneurons in other spinal regions. However, in all spinal regions, including the upper cervical spinal cord where BC and CM motoneurons were found, the pattern of dendritic distribution from different motoneurons was similar if their somata were located in the same region. For 15 motoneurons with well-stained dendrites, the mean rostral-caudal extent of the dendritic tree was 2,860 micrometers. The mean total dendritic length of three of these motoneurons measured 73,100 micrometers, almost four times larger than hindlimb motoneurons involved in planter reflexes. Despite the large size of the dendritic trees of BC and CM motoneurons, the surface areas of BC and CM cell bodies were smaller than most large hindlimb motoneurons. These quantitative differences in motoneuron dimensions may in turn be reflected by differences in the electrotonic properties of motoneurons in different motoneuron nuclei.

Journal ArticleDOI
TL;DR: In this paper, the authors present a systematic examination of non-convexity in the context of a classic problem in continuous-time investment theory-the optimal accumulation of capital by a firm maximizing its present value over an infinite horizon.
Abstract: That non-convex preferences or technologies cause problems for economic theory is well-known. In recent years there have been numerous contributions to the "nonconvexity problem" in the context of models with a finite-dimensional commodity space. In the capital theory context non-convexities have received explicit treatment in a few papers, in two distinguishable ways. The problem is cast either in a discrete-time framework (Aoki (1971), Rothschild (1971)) or in a continuous-time framework in which there are implicitly unbounded economies of scale in investment. The latter formulation leads to "jumps" in the state variable or lumpy investment, the standard problem treated is one of decreasing costs in the installation of new capacity (contributions include Chenery (1952), Dixit, Mirrlees and Stern (1975), Hartwick (1976), Manne (1967), Srinivasan (1967), Starrett (1978), and Weitzman (1970)). These types of analysis unfortunately ignore some of the most interesting problems associated with non-convexities in investment theory. In a discrete-time framework the important distinction between stocks and flows is blurred, while the capacity-installation problem, by admitting unbounded scale economies, excludes the "smoothing" of state variables that follows by allowing for eventually increasing costs of adjustment. In this paper we undertake a systematic examination of non-convexities' (or sometimes non-concavities) in the context of a classic problem in continuous-time investment theory-the optimal accumulation of capital by a firm maximizing its present value over an infinite horizon. While the results obtained are specific to this particular model we feel that they can be qualitatively extended to any capital-theory problem which can be cast in a continuous-time optimal-control-theory framework. There are various sorts of non2 convexities which can arise in these problems. First, there can be either stock or flow non-convexities; that is, non-convexities which are introduced into the net benefit function (the measure of the flow of benefits at each moment) through changes in the capital stock (state variable) on the one hand or changes in the flow of investment (control variable) on the other. If the benefit and transition functions are not concave in both these variables then necessary conditions are no longer sufficient for optimality and conventional marginal analysis fails. Non-convexities can also be introduced into the value functional, which has a stock dimension. In order to examine these different sorts of non-convexity problems we shall now present the basic economic problem. A firm is faced with the problem of maximizing the present value of discounted cash flow over an infinite horizon. Hence it chooses an investment programme I*(t) to maximize 00

Journal ArticleDOI
TL;DR: Vitellogenin and vitellin of Locusta migratoria have been purified from ovariectomized female haemolymph and from oocytes by a new procedure and the content of diacylglycerol is much lower in VN than in VG, which suggests the release of lipid within the oocyte.

Book ChapterDOI
01 Jan 1981
TL;DR: In a study of a series of mild and spinal varieties of multiple sclerosis the following histological changes have been found in the macroscopically normal white matter: marked astrocytic proliferation, some sclerosis of blood vessels, andOccasional unsuspected demyelination.
Abstract: In a study of a series of mild and spinal varieties of multiple sclerosis the following histological changes have been found in the macroscopically normal white matter: 1. Marked astrocytic proliferation. 2. Some sclerosis of blood vessels. 3. Some perivascular inflammation. 4. Occasional unsuspected demyelination.