Showing papers by "University of Saskatchewan published in 1989"

A reliability test system for educational purposes-basic data

Abstract: The IEEE Subcommittee on the Application of Probability Methods (APM) published the IEEE Reliability Test System (RTS) [1] in 1979. This system provides a consistent and generally acceptable set of data that can be used both in generation capacity and in composite system reliability evaluation [2,3]. The test system provides a basis for the comparison of results obtained by different people using different methods. Prior to its publication, there was no general agreement on either the system or the data that should be used to demonstrate or test various techniques developed to conduct reliability studies. Development of reliability assessment techniques and programs are very dependent on the intent behind the development as the experience of one power utility with their system may be quite different from that of another utility. The development and the utilization of a reliability program are, therefore, greatly influenced by the experience of a utlity and the intent of the system manager, planner and designer conducting the reliability studies. The IEEE-RTS has proved to be extremely valuable in highlighting and comparing the capabilities (or incapabilities) of programs used in reliability studies, the differences in the perception of various power utilities and the differences in the solution techniques. The IEEE-RTS contains a reasonably large power network which can be difficult to use for initial studies in an educational environment.

Cognition and Learning

Abstract: According to the dictionary of psychology, cognition is defined as a general term covering all the various modes of knowing—perceiving, remembering, imagining, conceiving, judging, and reasoning (Drever, 1969). In order to understand the relationship between cognition, as defined above, and learning, it will be necessary to examine the historical development of learning including changes in learning definitions. It will also be necessary to tease out the interaction between cognition and learning and the effect on cognitive learning theory as now loosely defined; some of the inherent problems; and some of the resulting implications for education.

Epidemiology of fractures of the distal end of the radius in children as associated with growth

Abstract: We determined the annual incidence of fracture of the distal end of the radius for patients of all ages and both sexes in the province of Saskatchewan, using two data sets: data on hospital admissions for 1970 through 1984, and data on physician billing for 1978 through 1985. The rate of occurrence of this fracture in children, by age and sex, was compared with longitudinal data on the velocity of growth that was collected during the same time for children from the same population. We compared the incidences of the fracture with the results of studies on the levels of activity in children and adolescents during growth. We also compared the age-specific incidence of the fracture in children with the incidence in adults. For both data sets, the age at the peak incidence of fracture of the distal end of the radius almost perfectly matched the age at which peak velocity of growth in height occurs for boys and girls. For girls, the peak incidence occurred between the ages of 11.5 and 12.5 years and for boys, between 13.5 and 14.5 years; these ages corresponded to the mean peak velocity of growth at 11.9 years for girls and 14.3 years for boys. The age-adjusted incidence of the fracture in male subjects was highest at fourteen years and was not exceeded by that in female subjects until fifty-three to fifty-four years.(ABSTRACT TRUNCATED AT 250 WORDS)

Refining the forced-choice method for the detection of malingering

Abstract: For seven years following head trauma, a 45-year-old restaurant owner had claimed that he was unable to work because of impaired memory. A specially designed forced-choice memory test yielded performance significantly below the chance level and thus indicated malingering. This case illustrates some means of increasing the utility of forced-choice malingering tests.

Speedup versus efficiency in parallel systems

Abstract: The tradeoff between speedup and efficiency that is inherent to a software system is investigated The extent to which this tradeoff is determined by the average parallelism of the software system, as contrasted with other, more detailed, characterizations, is shown The extent to which both speedup and efficiency can simultaneously be poor is bound: it is shown that for any software system and any number of processors, the sum of the average processor utilization (ie efficiency) and the attained fraction of the maximum possible speedup must exceed one Bounds are given on speedup and efficiency, and on the incremental benefit and cost of allocating additional processors An explicit formulation, as well as bounds, are given for the location of the knee of the execution time-efficiency profile, where the benefit per unit cost is maximized >

AP2 Gene Determines the Identity of Perianth Organs in Flowers of Arabidopsis thaliana.

Abstract: We have examined the floral morphology and ontogeny of three mutants of Arabidopsis thaliana, Ap2-5, Ap2-6, and Ap2-7, that exhibit homeotic changes of the perianth organs because of single recessive mutations in the AP2 gene. Homeotic conversions observed are: sepals to carpels in all three mutants, petals to stamens in Ap2-5, and petals to carpels in Ap2-6. Our analysis of these mutants suggests that the AP2 gene is required early in floral development to direct primordia of the first and second whorls to develop as perianth rather than as reproductive organs. In addition, our results support one of the two conflicting hypotheses concerning the structures of the calyx and the gynoecium in the Brassicaceae.

The social psychology of intergroup and international conflict resolution

Abstract: This volume on intergroup and international conflict resolution offers an overview of this social-psychological problem, and analyzes the factors involved in intergroup conflict.

Serous cystadenocarcinoma of the pancreas: a new entity?

Abstract: Microcystic cystadenoma of the pancreas is a well-recognized although rare pathological entity. All previously reported examples of this tumor have been uniformly benign in behavior. In this case report, we present a primary tumor of the pancreas that was histologically indistinguishable from microcystic adenoma, but which behaved in a malignant fashion. Metastases were found in the stomach and liver. We believe that this case represents a new entity, which we have termed "serous cystadenocarcinoma of the pancreas."

Magnetic penetration depth in single-crystal YBa2Cu3O7- delta.

Abstract: We report the first measurement of the magnetic penetration depth lambda(T,theta) in single crystals of YBa/sub 2/Cu/sub 3/O/sub 7-//sub delta/ (delta/similar to/0.1). Results are consistent with conventional s-wave pairing, and yield penetration depths of lambda/sub a//sub b/(0) = 1415 +- 30 A and lambda/sub c/(0)>7000 A, parallel and perpendicular to the basal plane, respectively. Comparative data on sintered YBa/sub 2/Cu/sub 3/O/sub 7/ also shown to be consistent with the single-crystal results. The ..mu../sup +/ spin rotation data, together with specific-heat results, indicate a two-dimensional carrier density of eta/sub 2//sub d/approx. =8 x 10/sup 14/ carriers cm/sup -2/ and a basal-plane effective mass of m/sub a//sub b//sup *//m/sub e/approx. =10. .AE

Customer cost of electric service interruptions

Abstract: An approach often used to estimate power-system reliability worth is to determine consumers' monetary losses resulting from service interruptions, i.e. the cost of unreliability. Previously, studies have been conducted to provide estimates of customer interruption costs, and a wide range of methodologies has evolved. There is no universal agreement on the appropriateness of methodologies to particular situations nor on the interpretation of the results obtained, but some appear to be more acceptable and useful to the industry than others. A survey is presented of the techniques available for estimating customer interruption costs, the rationale of those that are currently popular is discussed, and the application of such cost data in creating a composite customer damage function is explored. >

Hypersexuality with antiparkinsonian therapy.

Abstract: SummaryThirteen parkinsonian patients drawn from two large parkinsonism clinics experienced hypersexuality as a consequence of anti-parkinsonian therapy. The cases include only those whose sexual behavior on treatment became a concern to the patient's family or a social agency. The majority of patie

Development of the nerve fiber layer in the olfactory bulb of mouse embryos.

Abstract: The purpose of this study was to provide an ultrastructural description of the development of the olfactory nerve fiber layer (ONL) in the olfactory bulbs of mouse embryos. The developmental age of each embryo was determined by means of the Theiler staging system. During stages 17 and 18, the olfactory axons grew through the mesenchyme toward the cerebral vesicle; they were accompanied by a group of electron-dense cells which were referred to as peripheral glial progenitor cells (GPCs) because they ensheathed the adjacent axons. In Theiler stage 19-21 embryos, the axons and the peripheral GPCs grew dorsocaudally along the external surface of the bulb primordium forming a presumptive ONL immediately superficial to its glia limitans. Through small breaks in this glia limitans, the axons, but not the peripheral GPCs, penetrated into the marginal zone of the bulb primordium. Even though by the first half of stage 21 there were only short stretches of glia limitans separating the presumptive ONL from the marginal zone, there was no intermingling of the perikarya between the two layers. A definitive ONL could be identified by the second half of Theiler stage 21, by which time the glia limitans of the bulb primordium had totally disappeared. However, up to Theiler stage 24 of development the only cells to be found in this definitive ONL were the peripheral GPCs. Although in Theiler stage 25 and 26 embryos there was an additional population of less-electron-dense GPCs within the definitive ONL, these cells were likely derived from the previous group of peripheral GPCs rather than from cells newly emigrated from the deeper layers of the developing bulb. This developmental data necessitated a reevaluation of the cell lineages of the two glial cell types that reside within the ONL of the adult olfactory bulb.

A Prospective, Randomized Study Comparing Transparent and Dry Gauze Dressings for Central Venous Catheters

Abstract: Patients having central venous catheters for three or more days were prospectively randomized to receive a transparent (n = 58) or gauze (n = 57) dressing to compare the incidence of insertion site colonization, local catheter-related infection, and catheter-related sepsis. Quantitative cultures of the catheter insertion site (25 cm2) revealed significantly greater colonization (P less than or equal to .009) after 48 h in the transparent versus the gauze dressing group. Local catheter-related infection occurred significantly more often (P = .002) in the transparent (62%) than in the gauze group (24%). Seven episodes of catheter-related bacteremia occurred in the transparent group (16.6%) and none in the gauze group (P = .015). Stepwise logistic regression analysis revealed that cutaneous colonization at the insertion site of greater than or equal to 10(3) cfu/mL (relative risk, 13.16) and difficulty of insertion (relative risk, 5.39) were significant factors for catheter-related infection. These data suggest that transparent dressings are associated with significantly increased rates of insertion site colonization, local catheter-related infection, and systemic catheter-related sepsis in patients with long-term central venous catheters.

Distribution system reliability indices

Abstract: Distribution system reliability assessment is discussed. The assessment consists of measuring past performance and predicting future performance. The results obtained from two surveys dealing with US and Canadian utility activities are discussed, focusing on service continuity data collection and utilization. Service continuity statistics are summarized for those Canadian utilities that participate in the Canadian Electrical Association annual service continuity reports. >

Behavioral response of solitary fathead minnows,Pimephales promelas, to alarm substance.

Abstract: Single fathead minnows,Pimephales promelas, were exposed to a range of concentrations of conspecific skin extract. Their responses were observed qualitatively and quantified by a computer linked to an activity meter. The response of fathead minnows to skin extract is complex, involving at least three separate types of behavior. The minnows responded over a 1000-fold range of extract concentrations with combinations of dashing, freezing, slowing, and exploring. The latency of the response increased at the lowest extract concentrations, suggesting summation of sensory cell responses. At low stimulus concentrations, a period of exploratory behavior sometimes preceded the more typical alarm responses. The active space generated by the alarm substance in 1 cm2 of minnow skin may exceed 58,000 liters.

Effect of laminar flow velocity on the kinetics of surface recolonization by Mot(+) and Mot (-) Pseudomonas fluorescens.

Abstract: Computer-enhanced microscopy (CEM) was used to monitor bacteria colonizing the inner surfaces of a 1×3 mm glass flow cell. Image analysis provided a rapid and reliable means of measuring microcolony count, microcolony area, and cell motility. The kinetics of motile and nonmotilePseudomonas fluorescens surface colonization were compared at flow velocities above (120μm sec(-1)) and below (8μm sec(-1)) the strain's maximum motility rate (85μm sec(-1)). A direct attachment assay confirmed that flagellated cells undergo initial attachment more rapidly than nonflagellated cells at high and low flow. During continuous-flow slide culture, neither the rate of growth nor the timing of recolonization (cell redistribution within surface microenvironments) were influenced by flow rate or motility. However, the amount of reattachment of recolonizing cells was both flow and motility dependent. At 8μm sec(-1) flow, motility increased reattachment sixfold, whereas at 120μm sec(-1) flow, motility increased reattachment fourfold. The spatial distribution of recolonizing cells was also influenced by motility. Motile cells dispersed over surfaces more uniformly (mean distance to the nearest neighbor was 47.0μm) than nonmotile cells (mean distance was 14.2μm) allowing uniform biofilm development through more effective redistribution of cells over the surface during recolonization. In addition, motile cell backgrowth (where cells colonize against laminar flow) occurred four times more rapidly than nonmotile cell backgrowth at low flow (where rate of motility exceeded flow), and twice as rapidly at high flow (where flow exceeded the rate of motility). The observed backgrowth of Mot(+) cells against high flow could only have occurred as the result of motile attachment behavior. These results confirm the importance of motility as a behavioral mechanism in colonization and provides an explanation for enhanced colonization by motile cells in environments lacking concentration gradients necessary for chemotactic behavior.

Off-nominal frequency measurements in electric power systems

Abstract: Some power system protection applications require accurate estimates of voltage magnitude and frequency over a wide measurement range. Most digital techniques for measuring frequency have acceptable accuracy over a small range in the neighborhood of the nominal value. This paper presents a method for extending the measurement range of the Least Error Squares (LES) technique. The paper also examines the effectiveness of the technique and presents some results from simulated studies and laboratory experiments. It is essential to maintain the frequency of a power system close to its nominal value. Usually, frequency deviations in the range of two to three percent only are allowed for short durations of time. In this range, the Least Error Squares algorithm (LES) provides accurate estimates and is, therefore, suitable for implementing in most frequency relays. However, the measurement errors increase as the frequency deviation from the nominal value increases. During start-up and shut-down of a generator, its frequency varies over a wide range. If the generator is connected to a transformer, both the generator and the transformer can experience overexcitation. Excessive volts-perhertz (V/Hz) indicates that overexcitation has occurred. One method of estimating this parameter is to measure the voltage magnitude and frequency and then calculate volts-per-hertz. Voltsper-hertz relays that provide accurate measurements over 10 to 70 Hz range would be desirable for use on steam turbine driven generators. The frequency of the voltage of a thermal generator is low during start-up and shut-down procedures.

Forms and cycling of phosphorus in prairie and boreal forest soils

Abstract: The distribution of soil P among inorganic and organic forms was examined in prairie and boreal forest soil profiles from Saskatchewan, Canada. A sequential extraction procedure was employed to separate P into labile and stable inorganic (Pi) and organic (Po) fractions. Profile depth, climate, vegetation, and cultivation all had a major influence on the distribution of P which is attributed to differing intensities of pedogenic processes such as weathering and leaching, and their relationship to P transformations in the soil environment.

Role of aspartate aminotransferase and mitochondrial dicarboxylate transport for release of endogenously and exogenously supplied neurotransmitter in glutamatergic neurons.

Abstract: Evoked release of glutamate and aspartate from cultured cerebellar granule cells was studied after preincubation of the cells in tissue culture medium with glucose (6.5 mM), glutamine (1.0 mM),d[3H] aspartate and in some cases aminooxyacetate (5.0 mM) or phenylsuccinate (5.0 mM). The release of endogenous amino acids and ofd-[3H] aspartate was measured under physiological and depolarizing (56 mM KCl) conditions both in the presence and absence of calcium (1.0 mM), glutamine (1.0 mM), aminooxyacetate (5.0 mM) and phenylsuccinate (5.0 mM). The cellular content of glutamate and aspartate was also determined. Of the endogenous amino acids only glutamate was released in a transmitter fashion and newly synthesized glutamate was released preferentially to exogenously suppliedd-[3H] aspartate, a marker for exogenous glutamate. Evoked release of endogenous glutamate was reduced or completely abolished by respectively, aminooxyacetate and phenylsuccinate. In contrast, the release ofd-[3H] aspartate was increased reflecting an unaffected release of exogenous glutamate and an increased “psuedospecific radioactivity” of the glutamate transmitter pool. Since aminooxyacetate and phenylsuccinate inhibit respectively aspartate aminotransferase and mitochondrial keto-dicarboxylic acid transport it is concluded that replenishment of the glutamate transmitter pool from glutamine, formed in the mitochondrial compartment by the action of glutaminase requires the simultaneous operation of mitochondrial keto-dicarboxylic acid transport and aspartate aminotransferase which is localized both intra- and extra-mitochondrially. The purpose of the latter enzyme apparently is to catalyze both intra- and extra-mitochondrial transamination of α-ketoglutarate which is formed intramitochondrially from the glutamate carbon skeleton and transferred across the mitochondrial membrane to the cytosol where transmitter glutamate is formed. This cytoplasmic origin of transmitter glutamate is in aggreement with the finding thatd-[3H] aspartate readily labels the transmitter pool even when synthesis of endogenous transmitter is impaired in the presence of AOAA or phenylsuccinate.

Regional Metal Concentrations in Parkinson's Disease, Other Chronic Neurological Diseases, and Control Brains

Abstract: Metal deficiency or toxicity states have been recognized as a cause of several neurological disorders and are suspected in others. We analyzed four brain regions (frontal cortex, caudate nucleus, substantia nigra, and cerebellum) in 36 human brains for concentrations of 24 metals (Ag, Al, As, B, Be, Ca, Cd, Co, Cr, Cu, Fe, K, Pb, Mg, Mn, Mo, Na, Ni, P, Se, Ti, V, W, Zn). Regional metal concentrations, measured using atomic absorption and atomic emission spectroscopy, were compared between 9 Parkinson's disease (PD) brains, 15 brains from patients with other chronic neurological diseases, and 12 control brains. No significant metal concentration differences were noted between brains from PD and other chronic neurologic disease. However, parkinsonian brains (PD and parkinsonism secondary to neurofibrillary tangle disease) showed lower concentrations of magnesium in the caudate nucleus and copper in the substantia nigra than control brains. These findings may represent an etiologically important clue to parkinsonism.

Induced seismicity in mines in Canada—An overview

Abstract: Monitoring of mine-induced seismicity in Canada has improved with the expansion of regional seismograph networks into areas of active mining. However, the severity, and in some cases the frequency, of mine-induced tremors has increased as mining extends to greater depths and at accelerated rates of extraction. Because of the complex design and large areal extent of many mines (potash, coal and metalliferous), the most feasible and practical way to monitor these tremors at the present time is to deploy a network of seismometers in and on the surface above mines experiencing microearthquake activity. A few of these mines already have a network of seismometers deployed around them and plans are under way to deploy seismograph networks around other mines that have experienced some rather severe tremors in recent times. Six possible mechanisms for mine-induced tremors are described and the associated P- and S-wave radiation patterns presented. A comparison of actual seismic radiation patterns with theoretical predictions is a quick way to diagnose the potential source mechanisms. In addition, recognizing the pattern of microearthquake activity preceding larger tremors can be used to mitigate the potential effects of severe tremors.