Showing papers by "University of Alberta published in 1972"
TL;DR: In this paper, the authors present an approach for inventory management and supply of liquidity in the context of financial markets. But their approach is limited to a single bank and is not suitable for a large number of banks.
Abstract: I. Introduction, 79. â II. Inventory management and supply of liquidity, 80. âIII. Empirical findings, 87. â IV. Conclusions, 93.
418Â citations
TL;DR: Reciprocal activity in levator and depressor motoneurones can be evoked, or occurs spontaneously, in the partially de-afferented preparations, thus indicating the existence of a central locomotory rhythm generator.
Abstract: 1. The activity in identified motor units supplying the coxal levator and depressor muscles of the cockroach have been recorded in intact freely walking animals and in preparations after removal of all sensory input from leg receptors. 2. Reciprocal activity in levator and depressor motoneurones can be evoked, or occurs spontaneously, in the partially de-afferented preparations, thus indicating the existence of a central locomotory rhythm generator. 3. The reciprocal activity patterns recorded in the same motoneurones in intact freely moving animals are not identical to those recorded in partially de-afferented preparations. Thus, the production of normal rhythmic leg movements depends to some extent on sensory input from leg receptors, this input probably exerting tonic and phasic effects on the central rhythm generator. 4. An increase in the resistance to leg retraction during normal walking results in an increase in discharge rate of the levator and depressor motoneurones. This observation further demonstrates that rhythmic leg movements are not exclusively centrally controlled. The receptors responsible for this reflex effect are probably the trochanteral campaniform sensilla.
387Â citations
TL;DR: The following is a study of selection operating in the form of predation on the unusual characteristics of the Black stickleback.
Abstract: THE study of biological variation in terms of the organism's adaptation to its environment is a most revealing approach to understanding diversity. This is exemplified in the classical studies of the ecological genetics of the snail, Cepea nemoralis and various lepidopterans reviewed by Ford (1964) and Sheppard (1969). Such studies of natural selection in the wild have greatly contributed to our knowledge of such phenomena as adaptation, selective agents and their modes of action, intensity of natural selection, and maintenance of polymorphism, to name only a few. Most of this work has dealt with invertebrates. In the Queen Charlotte Islands, Canada, several populations of a vertebrate, the threespine stickleback, Gasterosteus aculeatus L., have diverged markedly from the typical G. aculeatus in respect to their morphology, ecology, and sometimes behaviour, much of the variation appears to be correlated with the presence or absence of predators. In Mayer Lake (latitude 53° 40'N, longitude 132° 02'W) individuals of one of these divergent populations are termed \"Black\" sticklebacks and are characterised by their large size, relatively long pelvic spines, average of seven lateral plates per side, and frequent absence of red pigmentation on the throat of sexually mature males. Black sticklebacks are parapatric with the typical, unkeeled, partially-plated form termed leiurus by European workers. Leiurus individuals are smaller than Black sticklebacks, have relatively short pelvic spines, an average of five lateral plates per side, and sexually mature males usually have red pigmentation on the throat. Various aspects of the ecology, life-history, and morphology of the two populations are discussed by Moodie (in press). The following is a study of selection operating in the form of predation on the unusual characteristics of the Black stickleback. Black sticklebacks, together with prickly sculpin, Cottus asper Richardson; cutthroat trout, Salmo clarki Richardson; dolly varden char, Salvelinus malma (Walbaum); and coho salmon, Oncorhynchus kisutch (Walbaum), are found in the lake proper. Leiurus occurs only in the inlet streams of the lake, where all other fish species are absent (Moodie, unpubl.).
276Â citations
TL;DR: The results establish that horseradish peroxidase (H-peroxidases) Compound I is not an enzyme peroxide complex, but a derivative in which the active site is oxidized.
254Â citations
TL;DR: The utilization of two crude oil samples of different quality at 4 and 30 C has been studied by using pure and mixed bacterial cultures obtained by enrichment procedures, showing that the n-saturate fraction had been preferentially used.
Abstract: The utilization of two crude oil samples of different quality at 4 and 30 C has been studied by using pure and mixed bacterial cultures obtained by enrichment procedures. Growth, emulsification, and utilization occurred readily at both temperatures. The crude oil residue is increased in specific gravity and readily sediments out of solution. A comparison of the chemical analysis of the oils by liquid and gas-liquid chromatographic procedures before and after growth showed that the n-saturate fraction had been preferentially used. Some utilization of the aromatic fraction also occurred. Enrichments obtained with a high-quality crude oil were not as effective in utilizing a lower quality crude oil as sole carbon source as a population enriched on the low-quality crude oil.
218Â citations
TL;DR: A new upper bound is obtained for Ď(2, k) for all k ⊞ 3 and a new lower bound forĎ(n, 3) is obtained, both for positive integers n and k.
217Â citations
TL;DR: In this paper, it was shown that the classical trajectories remain valid in the vicinity of classical turning points provided that the momentum-space semiclassical approximation is valid, the trajectories for elastic scattering in the various internal states differ only slightly, and the slopes of the elastic scattering potentials have the same sign.
Abstract: The time-dependent equations of the classical picture of inelastic collisions (classical-trajectory equations) are derived using the momentum-space semiclassical approximation. Thereby it is shown that the classical-trajectory equations remain valid in the vicinity of classical turning points provided that (a) the momentum-space semiclassical approximation is valid, (b) the trajectories for elastic scattering in the various internal states differ only slightly, and (c) the slopes of the elastic scattering potentials have the same sign. A brief review of the existing derivations of the classical-trajectory equations is given, and the general conditions for their validity are discussed.
201Â citations
TL;DR: In this paper, the authors derived the equations of the classical picture of atomic collisions, which describe the time dependence of electronic-quantum-state amplitudes as the nuclei move along a classical trajectory.
Abstract: This series of papers is concerned with the derivation of the equations of the classical picture of atomic collisions, $i\ensuremath{\hbar}\frac{d}{\mathrm{dt}}{d}_{i}(t)=\ensuremath{\Sigma}\stackrel{}{j}{h}_{\mathrm{ij}}(t){d}_{j}(t),$ which describe the "time" dependence of electronic-quantum-state amplitudes as the nuclei move along a classical trajectory These equations are derived in two ways In the first formulation, which coincides with the intuitive classical picture of the collision, the nuclear part of the wave function is treated as a superposition of narrow wave packets, each traveling along a classical trajectory In the second formulation, a semiclassical approach is used The validity and meaning of the two formulations are discussed and compared
168Â citations
TL;DR: In this article, a suite of 101 surface waters from the Mackenzie River drainage basin, Canada, was collected mainly during a 3-week period in the summer of 1969 and represents an instant in time during a period of average flow for most rivers in the basin.
151Â citations
TL;DR: In this paper, a unified formal treatment of the two-state potential curve-crossing problem in atomic collision theory is presented, and the case of close crossings analyzed in detail.
Abstract: A unified formal treatment of the two-state potential-curve-crossing problem in atomic collision theory is presented, and the case of close crossings analyzed in detail. A complete solution for this case, including necessary computations, is given using a suitable generalization of the linear model originally suggested by Landau, Zener, and Stueckelberg. Our solution is based upon a hierarchy of approximations concerned with (i) choice of a discrete basis set for electronic coordinates, (ii) semiclassical treatment of the nuclear motion, (iii) an appropriate model for the two-state electronic Hamiltonian, and (iv) a complete solution to that model.
151Â citations
TL;DR: It will be one of the features of this review to question the validity of always assuming that antigen- induced suppression and antibady-induced suppression act by different means.
TL;DR: Transport of nucleoside transport in human erythrocytes was further characterized using procedures that measured efflux from cells containing radioactive uridine or thymidine, indicating that both nucleosides are transported with equal facility by the same mechanism.
TL;DR: An array of bidirectionally coupled relaxation oscillators is proposed as a model of gastric electric-control activity, and its characteristics, such as intact and intrinsic frequency gradients and phase-lag patterns, were studied in anesthetized dogs.
Abstract: An array of bidirectionally coupled relaxation oscillators is proposed as a model of gastric electric-control activity. The characteristics of relaxation oscillators simulating control activity, such as intact and intrinsic frequency gradients and phase-lag patterns, were studied in anesthetized dogs. A marked intrinsic frequency gradient was found along the axis of the stomach, and a slight intrinsic frequency gradient around the circumference. The phase lag/cm decreased distally from the body of the stomach to the antrum. The model showed all these characteristics. Each oscillator in the array was represented by a system of two first-order nonlinear differential equations. The model was programmed on analog and hybrid computers.
TL;DR: Comparison between Japanese quail and human beings suggests that differences in response to noise are related to the type of signal system used by each species.
Abstract: Increasing ambient noise level causes male quail to (1) raise the intensity of individual separation crows, (2) increase the rate of crowing, and (3) increase bout length. Comparison between Japanese quail and human beings suggests that differences in response to noise are related to the type of signal system used by each species.
TL;DR: The hand preferences of 10 monkeys were recorded during the performance of 17 tasks which presented varying degrees of bait confinement, required varying numbers of sequential acts and required one handed or two handed manipulation.
TL;DR: Two non-linearities, rectification and phase-locking are described, which can reduce the absolute value of the frequency response measured using sine waves of all frequencies without changing its form.
Abstract: Widespread use has been made of linear systems theory to describe the input-output relations of receptors. The frequency response function of an insect mechanoreceptor, the tactile spine of the cockroach, has been estimated by using deterministic inputs (sines and step functions), deterministic inputs added to a stochastic, auxiliary signal (band-limited white noise), and a stochastic input alone. When a stochastic input is used, spectral analysis provides methods for estimating the coherence function as well as the frequency response function. The coherence function of the tactile spine is low, suggesting that the linear frequency response function is not a good characterization of the input-output relation of the receptor. Two non-linearities, rectification and phase-locking are described. Rectification can reduce the absolute value of the frequency response measured using sine waves of all frequencies without changing its form. Phase-locking changes the form of the frequency response function at high frequencies. Use of a stochastic auxiliary signal linearizes the input-output relations of the receptor in the sense that the cycle histograms obtained with sinusoidal inputs are more sinusoidal and the form of the frequency response function agrees with that predicted from the step response over a wider range of frequencies.
TL;DR: Use of the diffusion-controlled limit shows that p-cresol reacts in the unionized form over the experimental pH range, and that electrostatic interactions are therefore not responsible for the degree of complexity of the pH log rate profile.
TL;DR: Electron microscopy, together with quantitation using a tracing device linked to a digital computer, reveals that the red and white muscle fibers of Salmo gairdneri differ in diameter, organization of myofibrils, dimensions ofMyofilaments, volumes and surface areas of T system and sarcoplasmic reticulum, morphology of mitochondria, and content of mitochondaria, lipid, and glycogen.
Abstract: Electron microscopy, together with quantitation using a tracing device linked to a digital computer, reveals that the red and white muscle fibers of Salmo gairdneri differ in diameter, organization of myofibrils, dimensions of myofilaments, volumes and surface areas of T system and sarcoplasmic reticulum, morphology of mitochondria, and content of mitochondria, lipid, and glycogen. Biochemical studies show that the ATPase activity of white fibers is three times that of the red fibers. Actomyosin content of red fibers is higher than that of the white fibers. The functional significance of these differences between two fiber types is discussed.
TL;DR: Phage R17 was specifically labeled in the A protein with 3H-histidine, and in the RNA with 32P, and it was suggested that the penetration of phage RNA into the host cell may involve the injection of an A protein-RNA complex rather than free RNA.
TL;DR: In this article, Tetrahedral and cuboid finite elements with a linear variation of the pressure between the nodes are used for finding the natural frequencies and modes of an acoustic enclosure, which converges to the exact solution as 1 1 1/N2 where N is the order of a three-dimensional grid.
TL;DR: In this paper, an analytical method of predicting the ultimate load on eccentrically loaded weld groups is developed, which uses the true load-deformation response of the welds rather than some idealized one.
Abstract: Although present methods of investigating eccentrically loaded weld groups have produced safe designs, the factor of safety is, in general, unknown. An analytical method of predicting the ultimate load on eccentrically loaded weld groups is developed. The method uses the true load-deformation response of the welds rather than some idealized one. The validity of the approach has been verified by a testing program using 13 full-size specimens. By making use of the more accurate predictions presented, the factor of safety can be brought into line with that of other structural components and can be established at a constant value for all connections of this type.
TL;DR: In this article, the binding of p-crestol to native horseradish peroxidase was investigated by differential spectrophotometry, and the value 103 Kdiss = 3 m was obtained at neutral and acid pH; binding is not competitive with that of cyanide and hydroxide.
TL;DR: It was suggested that an optimal surface condition is required to bind reversibly prothrombin prior to conversion to thrombin, andAnticoagulant effects ascribed to acidic phospholipids may be due to irreversible binding of the clotting factors to lipid surfaces.
TL;DR: A pyocine selection system based on donor sensitivity and recipient resistance is described and appears to have future value as a generalized selective device for use after matings.
Abstract: Three strains of Pseudomonas aeruginosa were demonstrated to transfer double-drug resistance by conjugation to a P. aeruginosa recipient at frequencies of 10(-4) to 10(-2) per recipient cell. Two of the three strains also transferred to Escherichia coli at frequencies which were 10(3)- to 10(5)-fold lower, but the third strain could not be demonstrated to do so. The latter strain, however, conferred maleness on the Pseudomonas recipient. The transfer of streptomycin resistance was associated with the acquisition of streptomycin phosphorylase by both P. aeruginosa and E. coli recipients. Maximal broth mating frequencies were obtained with nonagitated cultures less than 1 mm in depth. A pyocine selection system based on donor sensitivity and recipient resistance is described and appears to have future value as a generalized selective device for use after matings.
TL;DR: It is concluded that for certain species there is strong evidence for a thyrotropin-inhibitory factor and a gonadotropin-releasing factor, and that the existence of a prolactin-Inhibiting factor is probable but not certain.
TL;DR: It is shown, by means of a transducer, that a transient opening movement takes place in relation to the silent period of electrical stimuli applied to oral mucous membrane while a steady biting force is maintained.
TL;DR: The boundary condition subroutines for the problem of electromagnetic induction in a two-dimensional model of a conductor with an arbitrary sub-surface conductivity structure are considered in this article.
Abstract: Summary General boundary conditions for the problem of electromagnetic induction in a two-dimensional model of a conductor with an arbitrary sub-surface conductivity structure are considered. Program subroutines for both E-polarization and H-polarization cases are given. These boundary condition subroutines can be used to replace the previously presented subroutines and allow the solution of any conductivity configuration within the conducting region by use of the same numerical technique. An example of a particular model with a sub-surface step structure is illustrated. Also, an improved method of calculating the surface values of the tangential component of the H-field (E-case) and the tangential component of the E-field (H-case) at the surface of the conducting region is given for the numerical solution. This new method uses a derivative approximated from the true functional form of the fields instead of a linear approximation and may be applied when a layered or subsurface anomaly is modelled. Some general discussion of the numerical method is given. At present there is considerable interest in the solution of the problem of electromagnetic induction in the Earth and the local perturbations of the fields when a lateral inhomogeneity is encountered. Jones & Price (1970) considered a twodimensional problem with a conducting half-space made up of two quarter-spaces of different conductivity, and Jones & Price (1971) considered a surface or buried region of rectangular cross-section of one conductivity surrounded by a region of different conductivity. Jones & Pascoe (1971) extended this work to consider a region of arbitrary shape and of several conductivities surrounded by a region of different conductivity and gave computer programs for the numerical solution of this problem for both the E-polarization (E parallel to the strike of the structure) and the H-polarization (H parallel to the strike of the structure) cases. The programs given by Jones & Pascoe (1971) may be used to consider long cylinders composed of several conductivities and of arbitrary cross-section embedded in a region of uniform conductivity, but cannot be used to solve the problem in which the surrounding region is not uniform. It is important to be able to solve the more general case in which the surrounding medium is a layered one and is not necessarily the same at great distances from the conductivity inhomogeneities on both sides. In
TL;DR: A saccate pollen grain with a branched pollen tube has been discovered within the pollen chamber of a fossil seed-fern ovule of Middle Pennsylvanian age, which suggests that microgametophytes comparable to those of living gymnosperms were produced by some Paleozoic pteridosPerms.
Abstract: A saccate pollen grain with a branched pollen tube has been discovered within the pollen chamber of a fossil seed-fern ovule of Middle Pennsylvanian age. This suggests that microgametophytes comparable to those of living gymnosperms were produced by some Paleozoic pteridosperms.