Showing papers by "University of Victoria published in 1979"
TL;DR: In this paper, a constantescapement feedback policy is shown to be optimal in maximizing expected discounted net revenue from an animal resource whose dynamics are described by a stochastic stock-recruitment model, provided that unit harvesting costs satisfy certain conditions.
306 citations
TL;DR: It is proved that for any graph G, ir (G) > γ(G)/2 and for any grpah G with p vertices and no isolated vertices, i(G) ≤ p-γ(G), which is the minimum cardinality taken over all maximal sets of vertices having no redundancies.
Abstract: A vertex x in a subset X of vertices of an undericted graph is redundant if its closed neighbourhood is contained in the union of closed neighborhoods of vertices of X – {x}. In the context of a communications network, this means that any vertex that may receive communications from X may also be informed from X – {x}. The irredundance number ir (G) is the minimum cardinality taken over all maximal sets of vertices having no redundancies. The domination number γ(G) is the minimum cardinality taken over all dominating sets of G, and the independent domination number i(G) is the minimum cardinality taken over all maximal independent sets of vertices of G. The paper contians results that relate these parameters. For example, we prove that for any graph G, ir (G) > γ(G)/2 and for any grpah Gwith p vertices and no isolated vertices, i(G) ≤ p-γ(G) + 1 - ⌈(p - γ(G))/γ(G)⌉.
225 citations
TL;DR: In this paper, a self-report battery for the assessment of hand, eye, foot and ear preference has been validated against behavioral tasks designed to measure the same four types of laterality.
Abstract: A self-report battery for the assessment of hand, eye, foot and ear preference, which has been validated against behavioral tasks designed to measure the same four types of laterality, is presented. Data showing the concordance between the inventory and the behavioral tests for a sample of 171 individuals is given. The mean degree of concordance between the behavioral and the questionnaire items was 90%. Additional analyses revealed that both forms of measurement provide similar descriptions of both individual and population lateral preference patterns. This report offers the questionnaire battery as a convenient and useful tool for the measurement of the four most common indices of laterality.
222 citations
TL;DR: Results show that Theileria-transformed cells express antigens which are recognised by effector cells and provide evidence that cell-mediated cytotoxic mechanisms function in immunity to ECF.
Abstract: In East and Central Africa the protozoan parasite Theileria parva causes a disease of cattle called East Coast fever (ECF). In Kenya alone between 60,000 and 85,000 cattle die from ECF every year1. Infected animals can recover from ECF either naturally2 or after treatment with tetracyclines3 or menoctone4 and are subsequently able to resist challenge with the homologous strain of parasite. That this acquired resistance is due to cell-mediated rather than humoral immunity has been suspected5,6 but never decisively shown. A major difficulty in studying immunity to ECF has been the lack of inbred animals for studying Theileria-specific immunity in the absence of allogeneic histocompatibility barriers. We have avoided this problem by measuring cell-mediated immune responses in a syngeneic system in vitro. Unidirectional mixed lymphocyte cultures (MLC) were set up using bovine peripheral blood lymphocytes (PBL) as responder cells and autologous cell lines transformed in vitro by T. parva as stimulator cells. In these cultures, DNA synthesis was induced in PBL from both normal and Theileria-immune animals. However, cytotoxic lymphocytes were induced only in cultures containing responder lymphocytes from Theileria-immune cattle. The results show that Theileria-transformed cells express antigens which are recognised by effector cells and provide evidence that cell-mediated cytotoxic mechanisms function in immunity to ECF.
98 citations
TL;DR: In this paper, a new method for solving problems in three-dimensional electromagnetic induction in which the Earth is represented by a uniformly conducting half-space overlain by a surface layer of variable conductance is presented.
Abstract: Summary. A new method for solving problems in three-dimensional electromagnetic induction in which the Earth is represented by a uniformly conducting half-space overlain by a surface layer of variable conductance is presented. Unlike previous treatments of this type of problem the method does not require the fields to be separated into their normal and anomalous parts, nor is it necessary to assume that the anomalous region is surrounded by a uniform structure; the model may approach either an E- or a B-polarization configuration at infinity. The solution is expressed as a vector integral equation in the horizontal electric field at the surface. The kernel of the integral is a Green’s tensor which is expressed in terms of elementary functions that are independent of the conductance. The method is applied to an illustrative model representing an island near a bent coastline which extends to infinity in perpendicular directions. None of the methods presently available for solving local problems in electromagnetic induction by a uniform source in a region of the Earth where the conductivity varies in three dimensions may be regarded as completely satisfactory. The finitedifference method of Lines & Jones (1973a,b) requires a great deal of computer time and storage and although it can be used to analyse models that approach a two-dimensional configuration at large distances in the two directions parallel to the electric field of the uniform inducing source, it is not capable of handling similar models that have a two-dimensional limit in the B-polarization rather than in the E-polarization mode. More efficient procedures have been developed (Raiche 1974; Weidelt 1975)’ but they are somewhat more restrictive in their applicability since they require the anomalous region to be entirely surrounded by a ‘normal’ (Le. layered) structure. It appears that no method has yet been devised for the treatment of the completely general problem in which the model may tend to either an E-polarization limit in the directions parallel to the electric field of the source, or a B-polarization limit in the directions parallel to the magnetic field of the source, or even both together in the same model as illustrated schematically in Fig. 1. Configurations of this type are not far-fetched;
75 citations
TL;DR: In this article, a measurement of the ion density in the flame front of an atmospheric-pressure, premixed air-propane flame is presented based on the sheath-convection model of current collection by a Langmuir probe.
52 citations
TL;DR: It is estimated that a period of approximately 30,000 years of storage of cells in 10% DMSO at −196 °C would pass before an accumulated x-ray dose from background radiation would reach a level, which upon cellular resurrection, would result in the equivalent lethal and chromosomal damage of an accute D 10 dose.
51 citations
TL;DR: It is suggested that an interaction of opiate-like peptides with central opiate receptors does not play any critical role in the kindling of seizures.
50 citations
TL;DR: The simplest explanation for the data is that both cross-links and monoadducts, formed by furocoumarins with DNA when exposed to 360-nm radiation, are capable of inducing mutations, and that monoadductions are repaired 20 times more efficiently than cross- links by the excision-repair pathway.
Abstract: The furocoumarin psoralen can form both monoadducts and cross-links with DNA when combined with 360-nm radiation, whereas the analog angelicin can form monoadducts only. Psoralen plus 360-nm radiation causes mutation induction with a slope of 2 (log-log plot) for a radiation-insensitive strain, whereas angelicin action with 360-nm radiation displays a slope of unity. For a radiation-sensitive mutant defective in the excision-repair pathway, the actions of both angelicin and psoralen plus 360-nm radiation exhibit one-target kinetics, but at higher exposures psoralen plus 360-nm radiation assumes a slope of 2. The excision-repair-defective strain is considerably more sensitive to the furocoumarins plus 360-nm radiation than is the radiation-insensitive strain, both for killing and mutation induction. The simplest explanation for the data is that both cross-links and monoadducts, formed by furocoumarins with DNA when exposed to 360-nm radiation, are capable of inducing mutations, and that monoadducts are repaired 20 times more efficiently than cross-links by the excision-repair pathway.
48 citations
TL;DR: The feasibility, advantages and relative efficiency of using this recursive representation of a tree T with M vertices to design algorithms on trees is discussed.
46 citations
TL;DR: In this article, a two-phase study was undertaken to test white and Canadian Indian school-children for racial identification and self-concept and found significant age, race, school, and sex differences in both preference and rejection.
Abstract: A two-phase study was undertaken to test white and Canadian Indian school-children for racial identification and self-concept. The objective was to establish attitudinal patterns and correlations using children in grades two, four and six at two schools (one integrated and one not). The first phase, using a picture test to measure preference, rejection, and identification found significant age, race, school, and sex differences in both preference and rejection. The second phase, using a short measure of self-concept, found sex, age, and school differences. Significant correlations between the two measures were found at the young age levels. Overall, with a few exceptions, the significant age, sex, race, and school differences were consistent with the conclusions drawn from previous research.
TL;DR: These results suggest that responses to visual-geometric illusions, mediated by optical or neural interactive mechanisms, show patterns of familial resemblance which may be based upon heritable factors.
Abstract: The Muller-Lyer and Ebbinghaus illusions were tested in 203 mother-father-offspring triads and 303 sibling pairs. Significant familial resemblances were found in all but the overestimated segment of the Ebbinghaus illusion. These results suggest that responses to visual-geometric illusions, mediated by optical or neural interactive mechanisms, show patterns of familial resemblance which may be based upon heritable factors.
TL;DR: It has been suggested that inverted versus upright handwriting position is an indicator of cerebral lateralization and the pattern of neuromotor control and Normative data on the prevalence of these handwriting positions was collected.
TL;DR: Poly(A)-containing RNA was isolated from maize embryos by chromatography on columns of oligo(dT)-cellulose and exhaustively digested with ribonucleases T2, T1, and A to reveal the presence of three 7-methylguanosine-terminated 'cap structures' of the type m7GpppNp.
TL;DR: Although mother-offspring resemblances were found for hand and ear, the pattern of correlation does not conform to that expected on the basis of genetic determination, suggesting a single causal mechanism is unlikely to account for all manifestations of lateral preference of limb and sense organ.
TL;DR: The functional response of the predacious mite Phytoseiulus persimilis Athias-Henriot to increases in the prey density of adult female Tetranychus urticae Koch was examined and a functional response curve having a curvilinear rise to a plateau was observed.
Abstract: The functional response of the predacious mite Phytoseiulus persimilis Athias-Henriot to increases in the prey density of adult female Tetranychus urticae Koch was examined. Previous studies on artificial substrates have described the functional response curve of P. persimilis to adult female prey as dome-shaped, because as prey density increased the predator was disturbed by prey activity.An experiment to determine the effect of artificial and natural substrates on the activity level of T. urticae was conducted. T. urticae showed a significant increase in activity on artificial substrates of plastic and waterproof paper compared with a substrate of excised bean leaf (Phaseolus vulgaris L.). Since prey activity was significantly influenced by substrate, the functional response of P. persimilis to adult female T. urticae was re-examined. P. persimilis exposed to various densities of T. urticae on excised bean leaf disks (5 cm2) showed a functional response curve having a curvilinear rise to a plateau as prey densities increased from 0.2 to 10.0 prey/cm2.The functional response curve predicted by Holling’s disk equation did not differ significantly from the observed functional response curve.The rate of successful search and the handling time predicted by the disk equation were 0.194 and 10.34 h respectively.
TL;DR: In this article, poly(A)-containing RNA was isolated by oligo(dT)-cellulose chromatography from maize embryos incubated in the presence of 32PO4.
TL;DR: A family of hypergraphs is exhibited which have the property that the minimum cardinality of a transversal is equal to the maximum cardinalities of a matching.
TL;DR: The possibility of sex differences in responses to visual-geometric illusions was investigated with the use of forty-five illusion variants and a sample of 221 observers and there were no significant differences between male and female observers.
Abstract: The possibility of sex differences in responses to visual-geometric illusions was investigated with the use of forty-five illusion variants and a sample of 221 observers No difference in illusion magnitude as a function of sex was found A second experiment measured illusion decrement and transfer of decrement to other illusion configurations Again there were no significant differences between male and female observers
TL;DR: Daily rates of net photosynthesis were closely correlated to division rates, suggest a direct relationship, and were maximal when cells were grown at 12:12 LD at both temperatures and 18:6 LD at 20 C, suggesting a physiological adaptation by photosynthetic units to short light periods.
Abstract: The effects of variable daylength and temperature on net rates of photosynthesis, dark respiration, and excretion of a unicellular marine haptophyte, Isochrysis galbana Parke, were examined and related to division rates. Six combinations of daylength (18:6, 12:12, 6:18 light:dark, LD) and temperature (20, 25 C) were used. Daily rates of net photosynthesis were closely correlated to division rates, suggesting a direct relationship, and were maximal when cells were grown at 12:12 LD at both temperatures and 18:6 LD at 20 C. A daylength of 6 hours decreased daily rates by decreasing the time for carbon uptake. Further, cells grown with this daylength had maximal chlorophyll a contents, suggesting a physiological adaptation by photosynthetic units to short light periods. A photoperiod of 18:6 LD at 25 C decreased daily rates of net photosynthesis by reducing the hourly rate of net photosynthesis via an unidentified mechanism. The importance of rates of net dark respiration in controlling daily net photosynthesis was small, with carbon lost during dark periods varying between 4 and 14% of that gained during light periods. Also, the influence of net excretion was small, varying between 1.0 and 5.5% of daily net photosynthesis.
TL;DR: In this paper, the authors investigated the behavior of the time-varying electromagnetic fields over the Vancouver Island region using a scaled analogue model and found that conductive channelling in the shallow seawater channel around the island is important for both E and H polarization of the inducing field and for all frequencies studied.
Abstract: The behaviour of the time-varying electromagnetic fields over the Vancouver Island region is investigated using a scaled analogue model. The results show that conductive channelling in the shallow seawater channel around the island is important for both E and H polarization of the inducing field and for all frequencies studied. It appears that channelled telluric currents flow along either side of Vancouver Island with some diffusion of current into the continent to the southeast of the island. For the H polarization case there is some evidence of current flow around the SE tip of Vancouver Island as well. The results also show the effects of local confinement of current whereby the direction of telluric flow is modified by the geometry of the seawater channel.
01 Jul 1979
TL;DR: In this article, it was shown that for a two-dimensional model the horizontal component of the electric field satisfies an integral equation on the surface of the thin sheet, which can be solved numerically for arbitrary sheet conductance.
Abstract: Lateral variations in the Earth's conductivity complicate considerably the calculation of the electromagnetic response of the Earth to an external inducing field which is uniform and horizontal. Although analytic solutions have been found for a few simple two-dimensional models in which the conductivity varies in one horizontal direction only, it is necessary, in general, to resort to numerical methods. If the conductivity variations of interest are confined to a surface layer it is often possible to represent the Earth mathematically as a uniform conducting half-space covered by an infinitely thin sheet of variable surface conductance. This simplification effectively reduces by one the number of dimensions over which the field equations need to be integrated numerically. It is shown that for a two-dimensional model the horizontal component of the electric field satisfies an integral equation on the surface of the thin sheet, which can be solved numerically for arbitrary sheet conductance. The accuracy of the numerical procedure is confined by applying it to E- and B-polarization induction in two adjacent half-sheets and then comparing the solution obtained with known analytic solutions of the same problem. In three-dimensions the two horizontal components of the surface electric field satisfy a coupled pair of double integral equations which can also be solved numerically for an arbitrarily varying conductance of the surface sheet.
TL;DR: This paper reviewed the considerable effort directed since the turn of the 1970s towards evaluation of these effects in Britain and classified studies according to quantitative methods used (simple statistical analysis, shift-share analysis and regression analysis) and emphasises the strengths of the latter over the others, showing that, without as yet being used entirely satisfactorily, models useful for policy assessment are developing.
Abstract: Regional policies may be assessed from at least three separate perspectives: their impact on the regional distribution of economic activity (their primary purpose), their aggregate efficiency effect on the economy (contribution to national output net of resource cost) and their financial impact on the national Treasury (net Exchequer costs). This paper reviews the considerable effort directed since the turn of the 1970s towards evaluation of these effects in Britain. So far as the impact of policy on the regional distribution of economic activity is concerned, the paper classifies studies according to quantitative methods used (simple statistical analysis, shift-share analysis and regression analysis) and emphasises the strengths of the latter over the others, showing that, without as yet being used entirely satisfactorily, models useful for policy assessment are developing. So far as aggregate policy effects (economic and financial) are concerned, there is more ground to be broken, although the outline o...
TL;DR: In general, the right eye performs better than the left, although there are interactions with sighting dominance and the direction of eye movement.
Abstract: Although monocular recognition scores for targets presented immediately after an eye movement do not differ, the two eyes show marked recognition asymmetries when both eyes are receiving inputs but a specific target is only presented to one. In general, the right eye performs better than the left, although there are interactions with sighting dominance and the direction of eye movement.
TL;DR: A critical review of the theory of status integration considers methodological, procedural, and theoretical problems as discussed by the authors, including the need to make post hoc explanations of aberrant findings, numerous possibilities for spurious effects, problems in defining categories such as age and occupation, problems of matching the characteristics of suicides with those of populations and ambiguities beclouding the application of the rules for using the theory.
Abstract: A critical review of the theory of status integration considers methodological, procedural, and theoretical problems. First, difficulties in adhering to some of the test principles established by Gibbs and Martin seem to preclude a thorough test of the theory. Second, a number of unsolved practical problems arise when attempting to test the theory with available data: (a) the need to make post hoc explanations of aberrant findings, (b) numerous possibilities for spurious effects, (c) problems in defining categories such as age and occupation, (d) problems of matching the characteristics of suicides with those of populations, and (e) ambiguities beclouding the application of the rules for using the theory. Finally, a serious question is raised about the validity of the status integration measure as a criterion for Durkheim's concept of social integration. The theory of status integration was proposed in 1958 by Gibbs and Martin and since then virtually no sociological study of suicide has lacked a reference to it.1 There have been critics, however: for example, Chambliss and Steele, Douglas, Hagedorn and Labovitz (a,b), and Li. This paper assesses the theory from three points of view: methodological, procedural and theoretical. The theory, derived from Durkheim, was designed to be tested against official, recorded information, and Gibbs and Martin have stipulated conditions under which these data are appropriate. The purpose here is to determine whether their stipulations would allow an empirical test of the theory. Further, a specimen study has been constructed, using data as suitable for testing the theory as are obtainable. Gibbs and Martin make only the modest claim that status integration theory can predict the rank order of suicide rates among appropriately defined groups, but simple
TL;DR: Since 1967, 74 studies reported in the literature using monaural stimulation elicited an hemispheric asymmetry, confirming original findings from dichotic listening studies.
Abstract: Sr/nmary.-Since 1967, 74 studies reported in the ljrerature using monaural stimulation elicited an hemispheric asymmetry, confirming original findings from dichotic listening studies. Dichotic listening was considered for a long time as being the only technique available to establish the existence of hemispheric asymmetry. The hypothesis of necessary competition between the stimuli to elicit an ear-advantage was generally accepted. In 1967 for the first time, Bakker and Simon independently reported an hemispheric asymmetry with monaural presentation, showing that stimulus competition was a sufficient but not necessary condition to elicit an ear-asymmetry. Since then numerous studies have confirmed these original findings, and in terms of asymmetry of ears, they support the results from dichotic listening studies. We found in the literature 74 studies reporting a significant hemispheric difference under monaural stimulation. These studies are listed below. The sources consulted for information were mainly references given by the authors listed in the bibliography and Psychological Ab~tracjs, Social Sciences Citatiolz Index ISI, and Ldnguage and Language Behavior Abstractl.
TL;DR: The first satellite observations of protons involved in the generation of IPDP (intervals of pulsations of diminishing periods) were reported in this paper. But the analysis of the satellite data was limited.
TL;DR: For instance, the authors states that education and assimilation were key components of Japanese colonial policy in Taiwan: assimilation of the island's native Taiwanese population (native islanders of Chinese ancestry) was an important goal; education was an instrument for attainment of this goal.
Abstract: Education and assimilation were key components of Japanese colonial policy in Taiwan: assimilation of the island's native Taiwanese population (native islanders of Chinese ancestry) was an important goal; education was an instrument for attainment of this goal. When during their fifty years of rule (1895–1945) Taiwan's administrators altered their interpretation or definition of assimilation, they modified educational policies accordingly. From beginning to end of the Japanese period in Taiwan its government intended education for native islanders to be a major tool of its assimilation policy, which although a consistent policy was not a static one.
TL;DR: In this article, it is demonstrated that the rate of gravitational energy loss from the authors' model free-fall system employing the widely accepted Bondi method agrees precisely with the results described in prior works.
Abstract: Suggested difficulties and criticism regarding earlier work is addressed. It is demonstrated that the rate of gravitational energy loss from the authors' model free-fall system employing the widely accepted Bondi method agrees precisely with the results described in prior works. Origins of the breakdown of the quadrupole formalism for free fall, previously indicated, are now delineated in detail. The role of source structure in the energy loss rate re-emerges, bringing into question much of the earlier work of others. The iterative technique with flat-space wave operators is justified. A new approach to quasiperiodic systems such as binary stars is described. Ideally modeled upon the actual birth of such systems, it evolves from an initially stationary configuration, again avoiding the problems and ambiguities regarding incoming radiation.