Showing papers by "University of Victoria published in 1995"

Sensitivity of climate simulations to the parameterization of cumulus convection in the Canadian climate centre general circulation model

Abstract: A simplified cumulus parameterization scheme, suitable for use in GCMs, is presented. This parameterization is based on a plume ensemble concept similar to that originally proposed by Arakawa and Schubert (1974). However, it employs three assumptions which significantly simplify the formulation and implementation of the scheme. It is assumed that an ensemble of convective‐scale updrafts with associated saturated downdrafts may exist when the atmosphere is locally conditionally unstable in the lower troposphere. However, the updraft ensemble is comprised only of those plumes which are sufficiently buoyant to penetrate through this unstable layer. It is assumed that all such plumes have the same upward mass flux at the base of the convective layer. The third assumption is that moist convection, which occurs only when there is convective available potential energy (CAPE) for reversible ascent of an undiluted parcel from the sub‐cloud layer, acts to remove CAPE at an exponential rate with a specified...

Strange Multiplicity: Constitutionalism in an Age of Diversity

Abstract: Part I. Demands for Constitutional Recognition: 1. The constitutional question raised by the politics of cultural recognition: six examples and three similarities 2. The mutual recognition of cultural diversity: three features of the common ground and three historical movements 3. The spirit of Haida Gwaii as a symbol of the age of cultural diversity 4. A constitutional dialogue in The spirit of Haida Gwaii Part II. Diversity and Contemporary Constitutionalism: 5. Anwering the constitutional question: an outline 6. Two languages of contemporary constitutionalism and the three schools of modern constitutionalism 7. The challenge of post-modernism and cultural feminism 8. The challenge of interculturalism Part III. The Historical Formation of Modern Constitutionalism: The Empire of Uniformity: 9. Constitutions ancient and modern 10. Seven features of modern constitutionalism 11. Example of forging the seven features: Locke and Aboriginal peoples 12. Vattel, Kant and their followers 13.The reform of diversity in Europe and the colonies 14. The American revolution and the guardians of empire today Part IV. The Historical Formation of Common Constitutionalism: The Rediscovery of Cultural Diversity, Part I: 15. The hidden constitutions of contemporary societies 16. Understanding constitutionalism: Wittgenstein and Hale 17. Examples of the three conventions: the Aboriginal and common-law system and the conventions of mutual recognition and consent 18. The Aboriginal and common law system and the convention of continuity 19.The Aboriginal and common law system and constitutional dialogue Part V. The Historical Formation of Common Constitutionalism: The Rediscovery of Cultural Diversity. Part II: 20. Diverse federalism and the conventions of mutual recognition, continuity and consent 21. Diverse federalism and continuity: the Quebec act and the ancient constitution 22. Diverse federalism, the three conventions and the American revolution 23. The modern attack on diverse federalism: the Durham report and its followers 24. Linguistic minorities and the three conventions: the form of reasoning appropriate to mutual recognition and accommodation 25. Intercultural citizens, gender differences and the three conventions Part VI. Constitutionalism in an Age of Cultural Diversity: 25. A summary of contemporary constitutionalism 26. Replies to four objections to contemporary constitutionalism 27. Two public goods of contemporary constitutionalism: belonging and critical freedom Conclusion: the philosophy and practice of contemporary constitutionalism Notes Bibliography Index.

Taking Serial Correlation into Account in Tests of the Mean

Abstract: The comparison of means derived from samples of noisy data is a standard pan of climatology. When the data are not serially correlated the appropriate statistical tool for this task is usually the conventional Student's t-test. However, frequently data are serially correlated in climatological applications with the result that the t test in its standard form is not applicable. The usual solution to this problem is to scale the t statistic by a factor that depends upon the equivalent sample size ne. It is shown, by means of simulations, that the revised t tea is often conservative (the actual significance level is smaller than the specified significance level) when the equivalent sample size is known. However, in most practical cases the equivalent sample size is not known. Then the test becomes liberal (the actual significance level is greater than the specified significance level). This systematic error becomes small when the true equivalent sample size is large (greater than approximately 30). ...

Latitudinal gradient of atmospheric CO 2 due to seasonal exchange with land biota

Abstract: THE concentration of carbon dioxide in the atmosphere is increasing, largely because of fossil-fuel combustion, but the rate of increase is only about half of the total emission rate1. The balance of the carbon must be taken up in the oceans and the terrestrial biosphere, but the relative importance of each of these sinks—as well as their geographical distribution and the uptake mechanisms involved—are still a matter of debate1-4. Measurements of CO2 concentrations at remote marine sites5-9 have been used with numerical models of atmospheric transport to deduce the location, nature and magnitude of these carbon sinks2,10-19. One of the most important constraints on such estimates is the observed interhemispheric gradient in atmospheric CO2 concentration. Published models that simulate the transport of trace gases suggest that the gradient is primarily due to interhemispheric differences in fossil-fuel emissions, with small contributions arising from natural exchange of CO2 with the various carbon reservoirs. Here we use a full atmospheric general circulation model with a more realistic representation of turbulent mixing near the ground to investigate CO2 transport. We find that the latitudinal (meridional) gradient imposed by the seasonal terrestrial biota is nearly half as strong as that imposed by fossil-fuel emissions. Such a contribution implies that the sinks of atmospheric CO2 in the Northern Hemisphere must be stronger than previously suggested.

Optimality conditions for bilevel programming problems

Abstract: The bilevel programming problem (BLPP) is a sequence of two optimization problems where the constraint region of the upper level problem is determined implicitly by the solution set to the lower level problem. To obtain optimality conditions, we reformulate BLPP as a single level mathematical programming problem (SLPP) which involves the value function of the lower level problem. For this mathematical programming problem, it is shown that in general the usual constraint qualifications do not hold and the right constraint qualification is the calmness condition. It is also shown that the linear bilevel programming problem and the minmax problem satisfy the calmness condition automatically. A sufficient condition for the calmness for the bilevel programming problem with quadratic lower level problem and nondegenerate linear complementar¬ity lower level problem are given. First order necessary optimality condition are given using nonsmooth analysis. Second order sufficient optimality conditions are also give...

Brain regions associated with retrieval of structurally coherent visual information

Abstract: An object's global, three-dimensional structure may be represented by a specialized brain system involving regions of inferior temporal cortex1–3. This system's role in object representation can be understood by experiments in which people study drawings of novel objects with possible or impossible three-dimensional structures, and later make either possible/impossible object decisions or old/ new recognition decisions about briefly flashed studied and non-studied objects. Although object decisions about possible objects are facilitated by prior study, there is no corresponding facilitation for impossible objects, thereby implicating a system that is specifically involved in the representation of structurally coherent visual objects4. Here we show, by positron emission tomography (PET), that increases in blood flow in inferior temporal regions are associated with object decisions about possible but not impossible objects, and that there are increases in the vicinity of the hippocampal formation associated with episodic recognition of possible objects.

Gestures Specialized for Dialogue

Abstract: A small group of hand gestures made during conversation (interactive gestures) seem to function solely to assist the process of dialogue rather than to convey topical information. The rate of interactive gestures was significantly higher when 27 dyads talked in dialogue than in sequential monologues, whereas the rate of other (topical) gestures did not change; this difference supports the theory that interactive gestures are uniquely affected by the requirements of dialogue. A second, microanalytic study tested hypotheses about the specific functions of interactive gestures by examining the responses of the person to whom the gesture was addressed. Predictions were correct for 78 of 88 gestures sampled randomly from a large database. These results support the conclusion that interactive gestures are an important means by which speakers can include their addressees in the conversation. Moreover, these gestures demonstrate the importance of social (dialogic) processes in language use.

Fair Play for Kids: effects on the moral development of children in physical education.

Abstract: Commitment to the principles of sportspersonship is an acknowledged goal for school physical education. However, few programs have been implemented to investigate moral development changes in physical activity settings. A field experiment was designed to examine the effect of participation in educational activities selected from Fair Play for Kids (1990) on the moral judgment, reason, intention, and prosocial behavior of children (N = 452) in the 4th through 6th grades. Six intact classrooms at each grade level (N = 18) were randomly assigned to the following groups: (a) control, (b) Fair Play for Kids curriculum during physical education only, or (c) Fair Play for Kids curriculum during all school subjects. Experimental protocol extended for 7 months of an academic year, and moral development indicators were assessed prior to and following the intervention. Using class as the unit of analysis, 3 × 2 (Group × Time) repeated measures analyses of variance revealed that both treatment groups were si...

Manipulating and documenting software structures using SHriMP views

Abstract: An effective approach to program understanding involves browsing, exploring, and creating views that document software structures at different levels of abstraction. While exploring the myriad of relationships in a multi-million line legacy system, one can easily loose context. One approach to alleviate this problem is to visualize these structures using fisheye techniques. This paper introduces Simple Hierarchical Multi-Perspective views (SHriMPs). The SHriMP visualization technique has been incorporated into the Rigi reverse engineering system. This greatly enhances Rigi's capabilities for documenting design patterns and architectural diagrams that span multiple levels of abstraction. The applicability and usefulness of SHriMPs is illustrated with selected program understanding tasks.

Parameterized Computational Feasibility

Abstract: Many natural computational problems have input consisting of two or more parts. For example, the input might consist of a graph and a positive integer. For many natural problems we may view one of the inputs as a parameter and study how the complexity of the problem varies if the parameter is held fixed. For many applications of computational problems involving such a parameter, only a small range of parameter values is of practical significance, so that fixed- parameter complexity is a natural concern. In studying the complexity of such problems, it is therefore important to have a framework in which we can make qualitative distinctions about the contribution of the parameter to the complexity of the problem. In this paper we survey one such framework for investigating parameterized computational complexity and present a number of new results for this theory.

The exact solution of certain differential equations of fractional order by using operational calculus

Abstract: In the present paper, the authors first develop an operational calculus for the familiar Riemann-Liouville fractional differential operator. This operational calculus is then used here to solve a Cauchy boundary-value problem for a certain linear equation involving the Riemann-Liouville fractional derivatives. Relevant connections are also indicated with the special cases of the equation, which were solved earlier by using other methods.

Stimulation of interleukin-8 production in epithelial cell lines by Helicobacter pylori.

Abstract: Following exposure to Helicobacter pylori cells, epithelial cell lines secreted interleukin-6 (IL-6) and IL-8 but not tumor necrosis factor alpha. Purified IL-6 alone did not stimulate IL-8 production from the cell lines tested, indicating that IL-6 was not an intermediary in IL-8 induction. Enhanced IL-8 secretion occurred in a time- and dose-dependent manner. None of 12 antibiotics tested exhibited a significant effect on IL-8-inducing activity, suggesting that preformed antigens were responsible for stimulating IL-8 secretion in vitro. Live bacterial cells caused the highest level of stimulation. Proteinase-digested and heated (56 or 100 degrees C) cells had significantly reduced stimulatory activities. Purified H. pylori lipopolysaccharide, but not exopolysaccharide, stimulated low-level secretion of IL-8, but only at high concentrations, while a water-extracted H. pylori antigen preparation was strongly stimulatory for HEp-2 cells. No reduction in IL-8-stimulatory activity was observed for H. pylori mutants negative for urease activity, production of a major lipoprotein, and motility. The noncytotoxic strain CCUG 915 stimulated lower IL-8 levels than other isolates. However, the otherwise isogenic cytotoxin-negative mutant 17874 delta vacA (S. H. Phadnis, D. Ilver, L. Janzon, S. Normark, and T. U. Westblom, Infect. Immun. 62:1557-1565, 1994) had the same IL-8-stimulatory ability as the parent strain, suggesting that surface proteins other than the vacuolating cytotoxin are involved in IL-8 stimulation.

An SIS epidemic model with variable population size and a delay

Abstract: The SIS epidemiological model has births, natural deaths, disease-related deaths and a delay corresponding to the infectious period The thresholds for persistence, equilibria and stability are determined The persistence of the disease combined with the disease-related deaths can cause the population size to decrease to zero, to remain finite, or to grow exponentially with a smaller growth rate constant For some parameter values, the endemic infective-fraction equilibrium is asymptotically stable, but for other parameter values, it is unstable and a surrounding periodic solution appears by Hopf bifurcation

Risky Business: The Paradoxical Meaning of Problem Behavior for Young Adolescents

Abstract: Concurrent and longitudinal relations among Canadian adolescents' problem behavior (PB), self-image, and peer relations were examined. The relationship of adolescents' perceptions of fun and risk w...

Marine shrimp aquaculture and natural resource degradation in Thailand

Abstract: Rising demand for shrimp in the developed nations has helped to foster a dramatic growth in marine shrimp aquaculture, particularly in South America and South Asia. In Thailand, Marine shrimp aquaculture is now an important earmer of foreign exchange. The growth in Production has been achieved through the expansion of the culture area and the adoption of intensive production methods. The conversion of near-shore areas to shrimp culture, however, is proving to have many consequences that impinge on the environmental integrity of coastal areas. This paper reviews the development of Thailand's marine shrimp culture industry and examines the nature of the environmental impacts that are emerging. It then discusses the implications these have for rural poor and the long-term viability of the culture industry.

Performance analysis of digital acoustic communication in a shallow water channel

Abstract: High data rate acoustic transmission is required for diverse underwater operations such as the retrieval of large amounts of data from bottom packages and real time transmission of signals from underwater sensors. The major obstacle to underwater acoustic communication is the interference of multipath signals due to surface and bottom reflections. High speed acoustic transmission over a shallow water channel characterized by small grazing angles presents formidable difficulties. The reflection losses associated with such small angles are low, causing large amplitudes in multi-path signals. In this paper we propose a simple but effective model for multipath interference, which is then used to assess the performance of a digital communication system operating in a shallow water channel. The results indicate that transmission rates in excess of 8 k-bits/s are possible over a distance of 13 km and channel depth of only 20 meters. Such a system offers improved performance in applications such as data collection from underwater sensors.

Randomized dynamic graph algorithms with polylogarithmic time per operation

Abstract: This paper solves a longstanding open problem in fully dynamic algorithms: We present the first fully dynamic algorithms that maintain connectivity, bipartiteness, and approximate minimum spanning trees in polylogarithmic time per edge insertion or deletion. The algorithms are designed using a new dynamic technique that combines a novel graph decomposition with randomization. They are Las-Vegas type randomized algorithms which use simple data structures and have a small constant factor. Let n denote the number of nodes in the graph. For a sequence of V(m0) operations, where m0 is the number of edges in the initial graph, the expected time for p updates is O( p log 3 n) (Throughout the paper the logarithms are base 2.) for connectivity and bipartiteness. The worst-case time for one query is O(log n/log log n). For the k-edge witness problem ("Does the removal of k given edges disconnect the graph?") the expected time for p updates is O( p log 3 n) and the expected time for q queries is O(qk log 3 n). Given a graph with k different weights, the minimum spanning tree can be maintained during a sequence of p updates in expected time O( pk log 3 n). This implies an algorithm to maintain a 1 1 e-approximation of the minimum spanning tree in expected time O((p log 3 n log U)/e) for p updates, where the weights of the edges are between 1 and U.

A Polymorphism of the Paraoxonase Gene Associated With Variation in Plasma Lipoproteins in a Genetic Isolate

Abstract: The Hutterite Brethren are a genetic isolate characterized by high indices of relatedness and a communal agrarian lifestyle. We hypothesized that variation of the paraoxonase (PON) gene that underlies the interindividual variation in plasma PON activity would be associated with variation in fasting plasma lipoprotein variables in this group. In 793 Hutterites, we measured plasma lipids, lipoproteins, and apolipoproteins and analyzed DNA for genotypes of the protein polymorphism at amino acid residue 192 of PON. We observed that genotypes of PON were significantly associated with variation in plasma concentrations of total, HDL, non-HDL, and LDL cholesterol, total triglycerides, and apolipoprotein (apo) B. Homozygotes for the low-activity variant of PON had significantly lower levels of plasma apoB-related biochemical variables than heterozygotes and homozygotes for the high-activity variant of PON. Homozygotes for the low-activity variant of PON also had significantly lower ratios of total choles...

G1 continuity of B-spline surface patches in reverse engineering

Abstract: When a clay model or industrial part is reverse engineered, B-spline surfaces are typically fitted to surface data points collected by a coordinate measuring machine, or, in more recent times, a laser scanner. The surface fitting procedure results in a patchwork of B-spline surfaces. Some of these patches may be required to blend smoothly with their neighbours to a specified degree of continuity. Past research on surface patch continuity has focused on Bezier surfaces. In the paper, some of those techniques are modified and applied to B-spline surfaces. An optimization method is presented which can achieve an approximate global G1 continuity of a given patchwork of B-spline surfaces. The method is illustrated by a complex physical model, which is digitized by a 3D laser scanner, and reverse engineered to create a smooth cad model.

Perfectionism, humor, and optimism as moderators of health outcomes and determinants of coping styles of women executives.

Abstract: Previous research has indicated that humor, optimism, and perfectionism are ubiquitous human tendencies and traits affecting the performance and coping styles of women in the work place. The purpose of the present series of studies was to provide a more rigorous test of the hypothesis that certain personality attributes buffer the impact of daily hassles on health outcomes among female executives. Three studies were conducted to examine how perfectionism, humor, and optimism moderate the deleterious effects of daily hassles on self-esteem, burnout, and physical health. Hierarchical multiple regression analyses revealed that all attributes significantly moderated the relationship between daily hassles and self-esteem maintenance, emotional exhaustion, and physical illness. A fourth study examined the correlations between high levels of perfectionism, humor, and optimism and female executives' use of different coping strategies and orientations. The results provide implications for the early socialization and management training of female executives working in stressful environments.