Showing papers by "Queen's University published in 1980"
453 citations
TL;DR: In this article, a method of estimating the energy of an impurity in a host electronic system using density-functional theory is presented, where the impurity ion plus its electronic screening cloud is treated as a unit and is used to define a quasiatom.
Abstract: A method of estimating the energy of an impurity in a host electronic system using density-functional theory is presented. The impurity ion plus its electronic screening cloud is treated as a unit and is used to define a quasiatom. The energy of the quasiatom is a functional of the host electron density in which it is immersed. In the simplest approximation it is given by the energy of the impurity in a uniform electron gas having a density equal to that of the host at the position of the impurity nucleus. This uniform-density approximation (UDA) is tested for light atoms in a variety of model and realistic situations and is found to be successful in reproducing qualitative trends. By developing a perturbation expansion for a weakly inhomogeneous host the UDA is shown to be the leading term in a rigorous expansion of the quasiatom energy in gradients of the host electron density, and corrections to second order in gradients are determined. As an example, these corrections are used in the calculation of the binding energy of a helium atom to a vacancy and excellent agreement with exact results is achieved. The perturbation expansion also suggests an ansatz for the quasiatom energy in which the host electron density is sampled by the quasiatom electrostatic potential. Tests of this ansatz are equally successful.
346 citations
TL;DR: In this paper, the authors conducted an interview with 34 senior executives in U.S. and Canadian firms, mainly in the electronics, machinery, and autoparts industry sectors, focusing on small-and medium-sized firms.
Abstract: Research on international marketing effectiveness was done by interviewing 34 senior executives in U.S. and Canadian firms, mainly in the electronics, machinery, and autoparts industry sectors. The study concentrated on small– and medium-sized firms. The findings indicate the relative importance of an information and control reporting system, organization of the international division, involvement of top management, R & D, technology, competitive pricing policy, marketing mix, and production function variables for international marketing effectiveness.
260 citations
TL;DR: It is reported here that patients carrying the analogous, autosomal recessive Chediak-Higashi (CH) gene have a profound defect in their ability to spontaneously lyse various tumour cells in vitro by either antibody-dependent or independent mechanisms.
Abstract: Immunodeficiency disorders have provided much information on the development and interaction of the various B and T lymphoid components in the immune system of man. As the lymphoid system becomes increasingly divided into functional subsets of cells it will be important to find immunodeficiencies affecting newly discovered cell types. Natural killer (NK) cells are a recently described but ill-defined subpopulation of lymphocytes which is thought to play an important part in surveillance against tumour development. Mice homozygous for the beige gene were found to have a selective deficiency in NK function and were more susceptible to transplantation of syngeneic tumours as predicted. We report here that patients carrying the analogous, autosomal recessive Chediak-Higashi (CH) gene have a profound defect in their ability to spontaneously lyse various tumour cells in vitro by either antibody-dependent or independent mechanisms. Since other cell-mediated cytolytic functions were relatively normal, these results suggest that the beige or Chediak-Higashi gene in both man and mouse controls NK function.
253 citations
TL;DR: In this article, an integral equation determining the density induced by an external perturbation is derived and the independent-particle response function for an inhomogeneous system appearing in this equation is obtained in a form convenient for numerical calculations, applied to the calculation of dipole polarizabilities of spherically symmetric atoms and ions.
Abstract: The linear response of an arbitrary electronic system is considered within the framework of the density-functional theory. An integral equation determining the density induced by an external perturbation is derived. The independent-particle response function for an inhomogeneous system appearing in this equation is obtained in a form convenient for numerical calculations. The equation is applied to the calculation of dipole polarizabilities of spherically symmetric atoms and ions. Results for the rare-gas atoms obtained by means of the local-density approximation are in good agreement with experimental values, except for the case of He. Polarizabilities are also evaluated for the alkali-metal ions, the alkaline-earth and other closed-shell metallic atoms.
209 citations
TL;DR: It is suggested that the equilibrium sex ratio is not simply a function of the amount of inbreeding or sib-mating, as suggested by Maynard Smith (1978) , but that the detailed breeding structure of the population must be taken into account.
195 citations
09 May 1980
TL;DR: The geophysical anatomy of the southern Belize continental margin and adjacent basins, including the morphology, sediments and organisms of the deep barrier reef and fore-reef.
Abstract: The geological setting of Belize reefs. The geophysical anatomy of the southern Belize continental margin and adjacent basins. The morphology, sediments and organisms of the deep barrier reef and fore--reef. The Perireefal sediments. The composition and age of limestones from the reef front, wall and fore--reef. Petrography of limestones from the wall and fore--reef. Comparative anatomy, organism distribution and late quaternary evolution of modern reef margins. Sedimentation and diagenesis on the deep seaward margin of modern reefs
194 citations
191 citations
TL;DR: It is reported here that failure of small threshold doses of one virally and one chemically induced transplantable leukaemia to grow out in syngeneic mice partly depends on a rapidly acting host defence mechanism.
Abstract: Natural killer (NK) cells, which occur at high levels in normal non-immune individuals of several species, have the capacity to lyse certain tumour cells in vitro, and have been proposed as a first level of defence against tumour growth in vivo1–3. Evidence for this comes mainly from the murine system, where certain FI hybrid or T-cell deficient mice with high NK activity resist growth of transplanted tumours better than do normal syngeneic controls with lower NK activity4–6. Recent studies of the beige mutation on the C57BL mouse strain background, previously proposed as an animal homologue of the human Chediak-Higashi syndrome7,8, have revealed a new model for analysing anti-tumour effector mechanisms in the intact syngeneic host9,10. The recessive beige gene (bgJ), which affects melanosome and granulocyte lysosome functions11,12, also causes a profound (but not total) depression of NK activity whereas other anti-tumour effector mechanism mediated by T cells and macrophages remain relatively intact13. It was important, therefore, to test the tumour susceptibility of beige mice as a first direct test of the hypothesis that NK cells are involved in surveillance against neoplasia. In partial confirmation of this hypothesis, we report here that failure of small threshold doses of one virally and one chemically induced transplantable leukaemia to grow out in syngeneic mice partly depends on a rapidly acting host defence mechanism. This mechanism is deficient in bg/bg mice, which develop palpable, progressively growing tumours faster and at a higher frequency than do phenotypically normal +/bg littermates.
169 citations
TL;DR: In this article, a modified overlapping sphere model was used for the electronic structure of methane, ethane, propane, isobutane and neopentane, which represented the only set of theoretically determined charges which can be related directly to experiment.
145 citations
TL;DR: It is shown that a female-biased sex ratio was expected in a model in which mating occurred within small local subgroups before population-wide dispersal of mated females.
Abstract: It has been shown by Fisher that a 1:1 sex ratio should be evolutionary stable as there would otherwise be a frequency-dependent advantage to the rarer sex1. Hamilton pointed out that Fisher's argument depends on the assumption of population-wide random mating, and showed that a female-biased sex ratio was expected in a model in which mating occurred within small local subgroups before population-wide dispersal of mated females. We consider here the sex ratio under some other models of dispersal in a geographically structured population.
TL;DR: In this paper, it was shown that alteration pipes initially had a chlorite core which graded laterally and vertically into a sericite-rich outer zone and finally into unaltered rocks.
Abstract: Pipe-shaped zones of altered rock containing disseminated and stockwork vein mineralization underlie each of the several Archean volcanogenic Cu-Zn ore lenses at the Millenbach mine. The rocks and mineralization have been metamorphosed first to hornblende hornfels assemblages, then retrograded to greenschist facies assemblages, but the metamorphism has not significantly affected the bulk composition of the rocks. The alteration pipes show a distinct mineralogical zoning in which a core zone containing either anthophyllite-bearing assemblages or massive chlorite grades outward into a biotite-rich zone characterized by a spotted texture. Normative calculations were used to show that alteration pipes initially had a chlorite core which graded laterally and vertically into a sericite-rich outer zone and finally into unaltered rocks. Similar zoning is present on the selvedges of individual sulfide veins within the alteration pipes. Volume was conserved, and a distinctive metasomatic trend developed across the alteration pipes and vein selvedges during the alteration process. The most characteristic features of the altered rocks are increased Fe and Mg, and decreased Ca and Na, relative to fresh rocks. K and Al have generally been added at the margins and leached at the cores of pipes. Chemical zoning across vein selvedges is similar. The zoning of alteration types on vein borders, and to a certain extent in the pipes as a whole, is interpreted as due to the progressive reaction of an initially homogeneous hydrothermal solution with the rocks as the fluid moved upward in, and outward from, permeable channelways in the discharge conduit of a submarine, sea water-dominated hydrothermal system. However, an additional cause of vertical, and to a lesser extent lateral, zoning is thought to have been the existence of a strong vertical thermal gradient, as well as lateral variations in the permeability in the pipes. The thermal gradient could have been caused by the discharge fluid column being under hydrostatic pressure and everywhere at its boiling point. The fluid was probably evolved sea water which was in equilibrium with the rocks at depth in the system and then degenerated, causing alteration and sulfide deposition as a result of cooling and chemical changes associated with boiling as it rose in the conduit systems.
TL;DR: Fat body from previously immunized diapausing pupae of the silkmoth, Hyalophora cecropia (Saturniidae), incubated in vitro, released antibacterial activity into the medium and incorporated 3H-leucine into the immunity proteins P1–P9.
Abstract: Fat body from previously immunized diapausing pupae of the silkmoth,Hyalophora cecropia (Saturniidae), incubated in vitro, released antibacterial activity into the medium and incorporated3H-leucine into the immunity proteins P1–P9. The release of antibacterial activity from fat body was also induced to some extent by injection of Ringer solution and, after 20 h in culture, by the injury of dissection.
TL;DR: One result supported the hypothesis that vision provides a frame of reference for judgments, and a second indicated the importance of vision to the maintenance of spatial memory.
Abstract: The influence of vision on auditory localization was assessed in an absolute identification paradigm using sighted and blindfolded subjects. Vision improved the accuracy of judgments directly in front of, to the side of, and behind the head of subjects in the horizontal plane, but had little relevance to vertical-plane localization. The exact form of the observed facilitation depended on the orientation of the speaker array to the head. In a second experiment involving sound localization in 10 visual environments, there was evidence for the operation of two distinct influences of vision on directional hearing. One result supported the hypothesis that vision provides a frame of reference for judgments, and a second indicated the importance of vision to the maintenance of spatial memory.
TL;DR: An interactive computer program is described which implements the procedure proposed in “A Formal System for Fuzzy Reasoning”, with each piece of evidence entered as a sentence, with an associated ‘degree of belief’ and ‘weight’; followed by a tentative conclusion.
TL;DR: In this article, a simple urban growth model with durable housing, in which all builders have perfect foresight, is presented, and qualitative differences between the economics of this model, the static class of models, and a class of dynamic models in which myopic expectations are assumed.
TL;DR: In this paper, the authors explored the dimensionality of the feedback construct, the relationships of feedback to individual performance and satisfaction, and the moderating effects of trust on these associations.
Abstract: The feedback of performance appraisal information is a critical communication activity in organizations. Research on the topic, however, has generally been limited to (1) treating feedback as an undifferentiated construct, and (2) not examining the important moderating impact of trust of the receiver in the sender. Using a sample of 100 managers, this study explores the dimensionality of the feedback construct, the relationships of feedback to individual performance and satisfaction, and the moderating effects of trust on these associations. Results indicate that various aspects of feedback are differentially related to performance and satisfaction under conditions of high and low trut. Importantly, the communication of performance appraisal information is found to be a more important correlate of satisfaction and performance for subordinates who express low trust in their superiors.
TL;DR: Two implication operators and resulting relationships between fuzzy sets are studied and the results compared with previous ones obtained with other implication operators are compared.
TL;DR: Numbers of cyclopoids, their nauplii, and Bosmina longirostris, fell rapidly in May — early June, and did not increase again until August, which coincided with the rise and fall in numbers of the young fish in the habitat.
Abstract: Young fish of six species in an open water community all began their exogenous feeding by taking nauplii and small cyclopoids of body length (less tail) of 0.1–0.3 mm. Appearance of larvae of the different species in the system was, however, sequential, the resource being utilized by the different species in turn. The sequence was: Perca flavescens, Percina caprodes, Pomoxis nigromaculatus, Ambloplites rupestris, Lepomisgibbosus and L. macrochirus. The larvae and juveniles changes their diet rapidly as they grew. Fish 10–14 days after hatching and 8–10 mm in length i.e. close to the beginning of the juvenile period, consumed larger-bodied prey items (including several genera of Cladocera) and had more diversified diets than the 4.5–6.0 mm first-feeding larvae. These differences, and progressive dispersal of the larger young from the area, served to minimize the chances of food competition between batches of young of different ages. The composition of the fish community of larvae changed from week to week as new species entered it, increased in size and departed. Patterns of food utilization changed accordingly. Numbers of cyclopoids, their nauplii, and Bosmina longirostris, fell rapidly in May — early June, and did not increase again until August. These changes coincided with the rise and fall in numbers of the young fish in the habitat.
TL;DR: This study demonstrates a good relation between the dose of nitroglycerin ointment and nitrogoglyin bioavailability and also provides therapeutic levels of nitreglycerin associated with substantial hemodynamic benefit in selected patients with cardiac failure.
Abstract: The aim of this study was to determine the bioavailability of nitroglycerin after application of nitroglycerin ointment in patients with heart failure and to examine whether a correlation exists between plasma nitroglycerin and its hemodynamic effects. The dose of nitroglycerin ointment selected was based on the prior hemodynamic response of individual patients to an intravenous infusion of nitroglycerin. Nine patients received 1 to 2 inches of nitroglycerin ointment on a single skin site (small dose group) and five patients received 4 inches (2 inches to two separate skin sites, large dose group). There was good correlation between the dose of nitroglycerin ointment and bioavailability (area under the plasma concentration time curve from 0 to 240 minutes) (r = 0.81, p mm Hg and in right atrial pressure from 14 ±7 to 11 ±6 mm Hg. There was a greater decrease in pulmonary capillary wedge pressure in the small dose group (31 percent) compared with the large dose group (13 percent) (p ng / ml at 60 minutes and remained at that level through 240 minutes. In the large dose group a plasma nitroglycerin level of 8.9 ± 4.0 ng / ml was achieved at 60 minutes and sustained through 240 minutes. Despite this plasma nitroglycerin level there was little decline in pulmonary capillary wedge pressure. This study demonstrates a good relation between the dose of nitroglycerin ointment and nitroglycerin bioavailability; nitroglycerin ointment also provides therapeutic levels of nitroglycerin associated with substantial hemodynamic benefit in selected patients with cardiac failure.
TL;DR: A revised version of a paper given at a Conference on Images of the Teacher and Issues in Curriculum Change, held at Queen's University, Kingston, Ontario in April 1979 is given in this paper.
Abstract: † This is a revised version of a paper given at a Conference on ‘ Images of the Teacher and Issues in Curriculum Change ‘, held at Queen's University, Kingston, Ontario in April 1979.
TL;DR: In this article, the effects on the ferric-ferrous ratio of varying individual components in a dry basaltic liquid have been determined at atmospheric pressure and constant oxygen fugacity (fO2).
TL;DR: In this article, a theory of extensions of von Neumann algebras by locally compact groups of automorphisms is developed, and necessary and sufficient conditions for an extension to be equivalent to a twisted crossed product extension are given.
Abstract: We develop a theory of extensions of von Neumann algebras by locally compact groups of automorphisms. The emphasis is on the description (from an algebraic point of view) of those extensions of a given von Neumann algebra by a given group which determine a fixed homomorphism from the group into the outer automorphism classes of the given algebra. Thus the study of such homomorphisms occupies a substantial part of the paper; for a large class of examples we are able to determine when such a homomorphism is split, and give a simple algebraic description of the extensions. We then give necessary and sufficient conditions (of an analytic nature) for an extension to be equivalent to a twisted crossed product extension, and give some applications to the study of representations of certain topological groups, and to approximately finite dimensional von Neumann algebras.
TL;DR: In this paper, the authors discuss who gets what, when and how in the context of housing in the Soviet Union, and propose a model for determining who receives what and when in the housing market.
Abstract: (1980). Who gets what, when and how? Housing in the Soviet Union. Soviet Studies: Vol. 32, No. 2, pp. 235-259.
TL;DR: It is shown that at concentrations similar to those required to inhibit thromboxane synthesis, UK-34787 inhibited arachidonate-induced aggregation and release reaction in platelet rich plasma from some, but not all, individuals.
TL;DR: The authors' observations are consistent with the view that all the Moorean taxa (excepting Samoana) are descendants of a single ancestral invasion, although the possibility of more than one invasion cannot be excluded.
Abstract: Land snails of the genus Partula Fer. inhabiting the island of Moorea in French Polynesia show complex patterns of partial speciation. The late H. E. Crampton described eleven species from the island. Two have since been relegated to the genus Samoana . Of the remaining nine taxa, as many as four may coexist at a single locality without evidence of hybridization. Nevertheless an allele appearing in any of the taxa is potentially capable of spreading to any of the others, although in the process it may have to pass through several intervening taxa. Large morphological, ecological and behavioural differences have evolved despite this potential for gene flow. The biological differences are not reflected in 20 enzyme loci surveyed by conventional starch-gel electrophoresis, nor in the numbers of chromosomes. It is clear that a significant part of the morphological divergence between taxa has taken place of Moorea. Our observations are consistent with the view that all the Moorean taxa (excepting Samoana ) are descendants of a single ancestral invasion, although the possibility of more than one invasion cannot be excluded. The pattern of differentiation shows at least two cases of circular overlap (‘ring species’), with diameters of 2 and 3 km, and several apparent examples of character displacement. Coexisting taxa tend to partition the available habitat, although the separation is never complete.
01 Jan 1980
TL;DR: Two methods employing cell frequency counts were found to be useful for investigating the internal anatomy of home ranges and emphasis is placed on describing approaches to answering questions on how animals use their home areas rather than the computer program package developed.
Abstract: Previously used methods to analyze radio tracking data have not generally taken advantage of all the information associated with location fixes Most early analyses were preoccupied with size and shape of home range Analysis strategies with options determined by study objectives, type of data and species-specific variables are described Descriptions can include cartographical, graphic and tabular depictions of distributions for spatial, habitat, and activity type utilization, direction and orientation as well as interaction potential measures A sample set of data from a red fox radio tracking study was used to demonstrate methods of analysis Analysis was performed interactively, which permitted the researcher to interrogate the data base with few inherent assumptions Computer algorithms for measuring area and depicting borders of home ranges were compared for consistency, sensitivity and richness for biological implications Two methods employing cell frequency counts were found to be useful for investigating the internal anatomy of home ranges Emphasis is placed on describing approaches to answering questions on how animals use their home areas rather than the computer program package developed A review of home range analysis and literature is also included
TL;DR: This model is used to investigate the evolutionary stability of the mechanism of sex determination found in the wood lemming which leads to a population sex ratio of three females to one male.
TL;DR: Ethanol, in quantities equivalent to those ingested during moderate drinking, may produce transient damage to the upper small intestine of man Conversely, ethanol may simply increase the susceptibility of the mucosa to the unavoidable trauma of suction biopsy.
Abstract: Previous studies by us indicated that ethanol in concentrations of 2.0–4.8% produced subepithelial blebs in the jejunum of the hamster. In the rat, due to rupture of the blebs, there was denudation of the villus tip epithelium. There are no similar data on humans. Ethanol, in quantities equivalent to 4.8–6.4 ounces of 80 proof whiskey (diluted to 20% w/v), was infused into stomachs of 20 normal human volunteers. Subjects were divided into groups (Gr) according to the amount or type of alcohol given, and the site of biopsies (SB). Gr 1∶60 g ethanol, SB=jejunum. Gr 2∶45 g ethanol, SB=jejunum. Gr 3∶45 g ethanol, SB=duodenum. Gr 4∶45 g ethanol as 4.8 oz 80 proof whiskey, SB=duodenum. To compare the morphology in the absence and presence of ethanol, biopsies were obtained from each volunteer before ethanol administration (control period). immediately after peak ethanol concentration in the duodenum or jejunum (ethanol period), and when intraluminal ethanol concentration fell towards zero (recovery period). The mean peak intraluminal ethanol concentrations in the four groups varied between 5.69% and 9.37% (w/v). Ethanol-induced damage was evaluated using strict preset criteria. Coded slides were evaluated by two observers. Suction biopsy damaged 18% of the villi even in biopsies obtained during the control period. Ethanol produced a statistically significant increase in the number of damaged villi (mean of all groups 45%, range∶32% in Gr 2 to 62% in Gr 3). During the recovery period the number of damaged villi fell to that seen in control period biopsies. Ethanol, in quantities equivalent to those ingested during moderate drinking, may produce transient damage to the upper small intestine of man. Conversely, ethanol may simply increase the susceptibility of the mucosa to the unavoidable trauma of suction biopsy. However, the histological and ultrastructural changes were similar to those induced by ethanol in small laboratory animals.