Showing papers by "Queen's University published in 1978"

Evolutionary stable strategies and game dynamics

Abstract: We consider a class of matrix games in which successful strategies are rewarded by high reproductive rates, so become more likely to participate in subsequent playings of the game. Thus, over time, the strategy mix should evolve to some type of optimal or stable state. Maynard Smith and Price (1973) have introduced the concept of ESS (evolutionarily stable strategy) to describe a stable state of the game. We attempt to model the dynamics of the game both in the continuous case, with a system of non-linear first-order differential equations, and in the discrete case, with a system of non-linear difference equations. Using this model, we look at the notions of stability and asymptotic behavior. Our notion of stable equilibrium for the continuous dynamic includes, but is somewhat more general than, the notion of ESS.

A Dual-Core Model of Organizational Innovation

Abstract: This paper examines the role of administrators and technical employees in the process leading to innovation adoption. A marked division of labor is found. The evidence indicates that two distinct i...

Test of optimal sampling by foraging great tits

Abstract: When great tits forage in an unknown environment containing two feeding places of different profitability, they first sample the two places and then exploit the more profitable one. The balance between sampling and exploitation shown by the birds is close to an optimal solution for maximising the number of food-items obtained during a feeding period.

Two categorical stages of object recognition.

Abstract: Visual object recognition was investigated in a group of eighty-one patients with right- or left-hemisphere lesions. Two tasks were used, one maximizing perceptual categorization by physical identity, the other maximizing semantic categorization by functional identity. The right-hemisphere group showed impairment on the perceptual categorization task and the left-hemisphere group were impaired on the semantic categorization task. The findings are discussed in terms of categorical stages of object recognition. A tentative model of their cerebral organization is suggested.

Hemodynamics at rest and during supine and sitting bicycle exercise in normal subjects

Abstract: To assess left ventricular function and to compare mean pulmonary wedge pressure and left ventricular end-diastolic pressure in the supine and sitting positions, 10 patients without demonstrable cardiovascular disease underwent hemodynamic studies at rest and during exercise In the two positions. At rest the values for heart rate were higher and the values for cardiac index, stroke index, left ventricular stroke work Index, mean pulmonary capillary wedge pressure and left ventricular end-diastolic pressure were lower in the sitting position. During both supine and sitting exercise left ventricular end-diastolic pressure, cardiac index, stroke index and left ventricular stroke work index increased significantly from the resting values. Comparison of data during exercise revealed higher values for heart rate and rate-pressure product and lower values for pulmonary capillary wedge pressure, left ventricular end-dlastollc pressure and stroke index in the sitting position; systolic and mean systemic pressure, cardiac index and left ventricular stroke work Index were similar during the two exercise periods. When absolute changes from rest to exercise were compared, the Increase In heart rate, systolic blood pressure, pulmonary capillary wedge pressure, left ventricular end-dlastollc pressure, cardiac index, stroke index, and left ventricular stroke work index were similar In the two positions. There was a good correlation between left ventricular end-diastolic pressure and pulmonary capillary wedge pressure at rest and during exercise in the two postures.

Trophic and spatial interrelationships in the fish species of an Ontario temperate lake

Abstract: Analysis of the fish faunas of Lake Opinicon and other small, cold temperate Ontario water bodies shows that the component species differ in body size, morphology, abundances, habitats, diurnal and seasonal habitat utilization patterns, diets, dietary changes with age, reproductive strategies, and population turnover rates. These differences are detailed. The number of species occurring in a lake is partly due to historic factors, the number of habitats available, and morphological, behavioral and ecological adaptations that, by channelling their owners towards alternative resources, permit species to co-occur. Diet overlap values between most species are low except for the congeneric bluegill and pump-kinseed sunfishes, where values are moderate. These are the two commonest species in the lake and other parameters must increase the ecological differences between these two species. Lake Opinicon is a highly variable ecosystem. Part of this variability stems from the seasonal nature of the environment and the fact that different resources reach their peak abundance at different times of the year. Ecological overlap levels between fish species fluctuate greatly in the course of the season as species switch from, or move on to, different resources. Population levels in different habitats also vary seasonally. Species adaptations and interaction patterns were presumably evolved over a long period; most of these adaptations undoubtedly developed before the component species colonized the lake.

Substitution Among Exhaustible Resources and Intergenerational Equity

Abstract: In Hartwick [3], it was shown that implicit in Solow's [10] model of intergenerational equity and exhaustible resources was the savings-investment rule: society should invest in reproducible capital precisely the current returns from the use of flows of exhaustible resources in order to maintain per capita consumption constant. Population was assumed to remain constant. In Solow [10] and Hartwick [3] it was assumed that there was only one exhaustible resource. Beckmann [1] & [2] has investigated optimal growth in models with many exhaustible resources. In this paper we consider the case of many exhaustible resources and derive results on substitution among resources and on the nature of paths of development. One of Beckrmann's results on substitution is analysed. Our approach is first to analyse efficient paths under the assumption of general savings functions and then to analyse efficient paths under the assumption of the special savings function referred to above. Our results indicate the Solow's existence theorem remains valid for the case of many exhaustible resources and some light is shed on the existence of paths for production functions not of the Cobb-Douglas form.

The Siberian Connection: A case for Precambrian separation of the North American and Siberian cratons

Abstract: The hypothesis that the Cordilleran geosyncline originated as an Atlantic-type continental margin by the rifting of an older Precambrian continental mass and the opening of a new ocean basin leads to the question of where the counterpart of the North American Precambrian craton may be. The Siberian platform—a large, discrete, older Precambrian craton, lodged in northeast Asia and surrounded by younger fold belts—is a likely candidate for the missing Precambrian continental fragment. The outline of its northeast margin fits the southwest margin of the North American Precambrian craton to produce a congruence of tectonic grain and age provinces. Both margins are overlapped by sediments of the same general type that began to accumulate about 1,500 m.y. ago, after the initiation of the separation.

Development and validation of a sex-role ideology scale

Abstract: Two studies are reported in which a scale measuring sex-role ideology was constructed, validated and cross-validated. Sex-role ideology was conceived as a system of sex-role beliefs forming a dimen...

Reproductive Habits in the Snow Goose: The Influence of Female Age

Abstract: Parental age influences reproductive performance in several avian species. Clutch size increases and nesting becomes earlier after the first year of breeding in certain species (e.g., Great Tit (Parus major), Kluijver 1951; Blacklegged Kittiwake (Ra Canada Goose (Bruntu cunudensis muxha), Brakhage 1965). Other species show no effect of female age and, in a few instances, clutch size declines with age (see Klomp 1970). The correlation of parental age with hatching and fledging success shows similar variability among species. In many colonial nesting species, young birds establish territories in peripheral or marginal habitats (e.g. Coulson 1971) either because of their inferior competitive ability in acquisition of central nest sites (Coach 1958, WynneEdwards 1962) or because adults, nesting earlier, establish central territories by precedence ( Coulson 1971). The Lesser Snow Goose ( Anser cuerulescens caerulescens; Delacour 1954) has been under study at a small nesting colony (3,000 pairs) at La P&rouse Bay, Manitoba (58”24’ N 94”24’ W) since 1968. Many of the birds of this colony are individually identifiable through coded plastic leg bands. In this paper, we examine the age of females as a factor affecting the spatial distribution of nests in the colony, reproductive success and the timing of nesting. Annual differences in the proportion of young birds that nest are also examined. Male geese that hatch at La P&rouse Bay seldom return to the colony after reaching reproductive maturity (Cooke et al. 1975). We have, therefore, been unable to establish a population of banded males of known age and to examine the influence of male age on reproduction.

Distribution of motoneurones to the neck muscles, biventer cervicis, splenius and complexus in the cat

Abstract: The distribution of motoneurones to the cat dorsal neck muscles biventer cervicis, splenius and complexus has been examined using the technique of retrograde horseradish peroxidase transport. A comparison was initially made of HRP uptake into motoneurones produced either by injecting HRP solution directly into a singly neck muscle or by exposing the cut ends of motor nerves to an HRP solution. The injection of HRP into single neck muscles was found to produce widespread labelling of motoneurones presumably due to diffusion of HRP into adjacent muscles. For the examination of individual motoneurone pools the technique of cut nerve exposure was therefore used. Labelled neck muscle motoneurones ranged from 10–70 μ in diameter, but the majority of cells had diameters which were less than 40 μ. Most cells were located in the ventromedial nucleus and along the medial border of the ventral horn. In these regions there was considerable overlap between the motoneurones pools of the three neck muscles examined. In addition, some splenius motoneurones were located in the nucleus of the spinal accessory nerve. Labelled neck muscle motoneurones were also located in areas not usually considered to contain motoneurones such as the commissural and centrodorsal nuclei and in the ventral commissure.

The Optokinetic Basis of Head-bobbing in the Pigeon

Abstract: 1.Head-bobbing of pigeons during walking and landing was studied using high-speed motion photography. 2.The analysis of film records indicated that head-bobbing whilst walking consists of two phases: one where the head is ‘locked’ in space but moves backward relative to its forward moving body; and another where it is thrust rapidly forward to a new position. 3.The fact that head-bobbing is abolished when pigeons walk on a treadmill suggests it is primarily a visual response rather than an equilibratory response. 4.Data are presented which show that stabilization during the ‘lock’ phase allows a small degree of slippage which is the probable source of error signals for compensatory head movements. 5.The head-bobbing that appears to occur during landing is shown to be illusory.

Plagioclase buoyancy in basaltic liquids as determined with a centrifuge furnace

Abstract: Plagioclase buoyancy experiments have been carried out in a high-temperature centrifuge furnace using seventeen basaltic liquids and plagioclase crystals of three compositions: An89, An76 and An55. The results show that the floating tendency of plagioclase in basaltic liquids is at least 0.03 g/cm3 greater than indicated by the calculations. If this correction factor is applied to calculations of plagioclase buoyancy in the Skaergaard Intrusion, it is found that the plagioclase crystals in the lower and middle zones were less dense than the coexisting liquids. Other phenomena relevant to crystal transport in basaltic liquids were observed in the centrifuge experiments. These included crystal flotation by rising bubbles, plagioclase sinking because of the formation of plagioclase-magnetite composite grains, graded bedding of olivine and magnetite, and more than 60% intercumulus basaltic liquid between settled olivine crystals.

Kirillov's character formula for reductive Lie groups

Abstract: Inventiones math. 48, 2007-220 (1978); on-line version. Kirillov’s famous formula says that the characters X of the irreducible unitary representations of a Lie group G should be given by an equation of the form (Φ) χ(exp x )= p(x) −1 Ω e i(λ,x) dµΩ(λ) where ω =Ω (X )i s aG-orbit in the dual g ∗ ft he Lie algebrag of G, µΩ is Kirillov’s canonical measure on Ω, and p is a certain function on g ,n amely p(x )= det 1/2 {sinh(ad(x/2)) /ad(x/2)} at least for generic orbits Ω [10]. This formula cannot be taken too literally, of course (the integral in (Φ) is usually divergent), but has to be interpreted as an equation of distributions on a certain space of test functions on g. To make this precise, denote by g o an open neighborhoodod of zero in g so that exp : g → G restricts to an invertible analytic map of g o onto an open subset of G. For our purposes, the formula (Φ) should be interpreted as saying that (Φ � )t r g ϕ(x)π(exp(x)) dx = Ω g e i(λ,x) ϕ(x) p(x) −1 } dµΩ(λ) for all C ∞ functions ϕ with compact support in g o . (Here π is the representation of G with character χ.) Of course, Kirillov’s formula does not hold in this generality. It is in fact a major problem in representation theory to determine its exact domain of validity. In this paper we shall show that Kirillov’s formula holds for the characters of a reductive real Lie group which occur in the Plancherel formula. Actually, we shall deal in detail only with the discrete series characters. The formula for the other characters can then be reduced to the formula for the discrete series characters by familiar methods. (Duflo [3]). Kirillov’s formula for the discrete series is a consequence of a formula relating the Fourier transform on g with the Fourier transform on Cartan subalgebras of compact type by means of the invariant integral. This is the form in which Kirillov’s formula will be proved.

Processing spatial information and the selective-masking effect.

Abstract: When a mask follows tachistoscopic presentation of a letter string, the performance on the middle letters is reduced more than at the ends, the selective-masking effect. The ends-first explanation for selective masking holds that the letter string is identified from the ends to the middle. As a result, the end items escape the effects of the mask. Using a bar-probe task, we present three kinds of evidence both questioning the ends-first account and offering an alternate based on spatial-localization processes. The first experiment exposed the role of spatial localization by using words to minimize identification factors. The second obtained a comparable selective-masking effect with pseudowords; again, the pattern of errors favored the localization account. A final experiment tested predictions derived from the localization view in response to inconsistencies posed by the sequential-identification idea.

Discrimination in evaluative judgments against foreign-accented job candidates

Abstract: The purpose of this study was to determine the effects of the ethnicity of speakers, as suggested in accents, on judgments of suitability for a job, and to establish the relationship between listen...

Subjective motion and acceleration induced by the movement of the observer’s entire visual field

Abstract: Three experiments were carried out to trace the developmental time course of apparent subjective rotation induced by rotating a tall striped drum around an observer. In Experiment 1, rotation of the drum led to increasingly frequent reports of subjective rotation over the first 30 sec of stimulation by the optokinetic stimulus, after which subjects experienced mostly apparent subjective rotation and a small amount of drum rotation. In Experiment 2, using a magnitude estimation technique to assess the speed of drum and subjective rotation, subjects reported subjective acceleration and drum deceleration of about the same magnitude over the first 30 sec of the 1-rain trial, followed by a steady level of subjective rotation with some residual drum movement. In Experiment 3, using three different drum speeds, it was found that the speed of steady-state rotation, as well as subjective acceleration and drum deceleration, are linear functions of the speed of the inducing stimulus. Implications of these observations towards the explanation of how we perceive a stable environment during locomotion are discussed.

Nearshore fish habitat utilization and species associations in Lake Opinicon (Ontario, Canada)

Abstract: The bulk of Lake Opinicon fish biomass is concentrated in the physically diverse inshore areas. Quantitative analysis of the community compositions of the various inshore habitat types (weedy inlets, sandy shallows, rock shelf, gravel, etc.) showed that each supported a characteristic assemblage of fishes with a relatively constant species and year class composition. This was maintained throughout the season despite a drop in fish biomass in late summer when there was a progressive movement into the offshore waters.

Psychiatric aspects of dermatitis artefacta

Abstract: Fifty patients with dermatitis artefacta were investigated psychiatrically over several years and twenty-sic of these were seen independently by a clinical psychologist. The psychological investigations suggest a personality structure characterized by inward-looking self-centered attitudes leading to increasing isolation. The psychiatric investigations suggest a background of emotional disturbances during the formative years and in later life often resulting in feelings of isolation and insecutity. The onset of dermatitis artefacta is very frequently related to definable precipitating events which vary according to age and life situations. The visible skin lesions can be understood as an attempt at non-verbal communication subserving an appeal function. Therapeutic methods and prognosis are discussed in some detail.

Induction of a tumor with greatly increased metastatic growth potential by injection of cells from a low-metastatic H-2 heterozygous tumor cell line into an H-2 incompatible parental strain

Abstract: An H-2 heterozygous sarcoma, MDAY, originally induced with methylcholanthrene in an (A X DBA/2)F1 ((H-2a X H-2d) hybrid host was selected for growth in the H-2d homoxygous parental DBA/2 strain by serial intraperitoneal transplantation of ascites tumor cells. An apparent variant, designated MDAY-D2, was obtained which showed the expected loss of the private and public H-2Kk haplotype antigens normally associated with the A strain parent and the original MDAY tumor. Comparison of the original and variant lines revealed a wide variety of a cell surface antigen and receptor differences. Both tumors were found to be highly anaplastic and histologically unclasssifiable. Examination of the two tumor lines growing in vivo revealed a remarkable difference in their metastatic growth potential. The original MDAY line showed little propensity to spread to any organ site, with the occasional exception of liver, after subcutaneous inoculation of (A X DBA/2)F1 mice. In striking contrast, there was a rapid and massive spread of MDAY-D2 to liver, spleen, lungs and kidneys within 12-16 days: liver and spleen could be totally replaced by tumor within 2-3 weeks. These characteristics were observed in both (A X DBA/2)F1 and DBA/2 mice. The tendency to metastasize, as well as loss of the H-2Kk haplotype, appeared stable and irreversible. Although the precise origin of MDAY-D2 is not clear, its metastasizing properties are unique, making it a useful and desirable model to study the biology of metastasis.