Showing papers by "Concordia University published in 1980"
TL;DR: Suggestions as to the possible sites of interaction of drugs of abuse with brain stimulation reward circuitry are speculative, and are advanced as potentially heuristic working hypotheses.
Abstract: The finding that animals will work for electrical stimulation of some but not all parts of the brain has prompted the view that there are specialized brain circuits which subserve reward function. Two synaptic links in this circuitry have been partially identified. Studies of the effective stimulation parameters indicate that the directly activated fibers are usually high-frequency-sensitive, fast-conducting, myelinated fibers. Pharmacological studies suggest that all reward sites tested are afferent to a critical dopaminergic synapse; the myelinated, reward-relevant fiber of the medial forebrain bundle may synapse directly on the dopamine link. Dopamine blockers block self-stimulation regardless of electrode placement, and dopamine agonists are rewarding in their own right; thus the critical dopaminergic synapse plays both a necessary and (with its normal efferents) a sufficient role in reward function. Several drugs of abuse can facilitate self-stimulation, and it is hypothesized that they do so by a direct action on the same neural substrate. Amphetamine and cocaine seem to act directly in the critical dopamine synapse. Opiates might act at the dopamine synapse or cell bodies, or might act on dopamine afferents. Ethanol, barbiturates and benzodiazepines have not been extensively explored, but if their reported facilitations of self-stimulation are reliable they might be suggested to cause them by a naloxone-reversible inhibition of noradrenergic function, which disinhibits rather than directly excites the dopamine reward link. These suggestions as to the possible sites of interaction of drugs of abuse with brain stimulation reward circuitry are speculative, and are advanced as potentially heuristic working hypotheses.
324 citations
01 Apr 1980
TL;DR: Recognition algorithms, data bases, character models, and handprint standards are examined and Achievements in the recognition of handprinted numerals, alphanumerics, Fortran, and Katakana characters are analyzed and compared.
Abstract: Based on a study of the extensive literature in handprint recognition, this paper presents a survey in this challenging field. Recognition algorithms, data bases, character models, and handprint standards are examined. Achievements in the recognition of handprinted numerals, alphanumerics, Fortran, and Katakana characters are analyzed and compared. Data quality and constraints, as well as human and machine factors are also described. Characteristics, problems, and actual results on on-line recognition of handprinted characters for different applications are discussed. New emphases and directions are suggested.
297 citations
TL;DR: In this paper, the authors conducted an interview with 34 senior executives in U.S. and Canadian firms, mainly in the electronics, machinery, and autoparts industry sectors, focusing on small-and medium-sized firms.
Abstract: Research on international marketing effectiveness was done by interviewing 34 senior executives in U.S. and Canadian firms, mainly in the electronics, machinery, and autoparts industry sectors. The study concentrated on small– and medium-sized firms. The findings indicate the relative importance of an information and control reporting system, organization of the international division, involvement of top management, R & D, technology, competitive pricing policy, marketing mix, and production function variables for international marketing effectiveness.
260 citations
TL;DR: Findings suggest that a certain population of dopaminergic neurons directly participates in what is probably a multiple-link circuitry subserving positive reinforcement.
254 citations
TL;DR: The activities of catalase, peroxidase, indoleacetic acid (IAA) oxidase and peroxide levels in cucumber plants during and after chilling were determined and the increase in peroxide and IAA oxidase activity may inactivate or destroy IAA and thus retard growth.
Abstract: The activities of catalase, peroxidase, indoleacetic acid (IAA) oxidase and peroxide levels in cucumber plants during and after chilling were determined. During 96 hours at 5 C and 85% relative humidity, catalase activity declined, IAA oxidase activity increased, and peroxide concentrations increased. Peroxidase activity was not affected by chilling. When chilled plants were returned to 25 C to recover, enzyme activities and peroxide concentration were restored to their prechilling levels. The increase in peroxide and IAA oxidase activity may inactivate or destroy IAA and thus retard growth.
202 citations
01 Jan 1980
TL;DR: The Euclidean parallels postulate as discussed by the authors states that through any point in a plane of a given straight line there is one, and only one straight line which does not intersect the given line.
Abstract: This chapter elaborates the spacetime and geometry. Mathematics in the modern sense may be said to have originated in the work of Euclid. It is found that prior to this time the various truths of geometry had been treated as isolated, or mutually independent. The essence of the axiomatic method in geometry is to demonstrate that the truth of all geometric theorems depends solely on the truth of a proper subset of them, the axioms, from which all of the former are derivable. The famous Euclidean parallels postulate was thought to lack the self-evident character of the remaining axioms. The parallels postulate may be expressed as the claim that through any point in a plane of a given straight line there is one, and only one straight line which does not intersect the given line. It appeared to Euclid's successors that such an assumption marred the perfection of his system in so far as it involves not simply line segments but the entire Euclidean plane extended to infinity.
171 citations
TL;DR: Animals will work for a reward consisting of electrical stimulation at certain specific sites within the brain, James Olds termed these ‘pleasure centers', but recent work suggests that, with some minor modifications, the concept still provides a useful experimental paradigm.
157 citations
TL;DR: Some common textbook approaches introduce the concept of equation through problem solving and no doubt manage to reach a good number of students as discussed by the authors, however, to some pupils, trans lating a word problem into an equation is tantamount to translating it into a language unknown to them.
Abstract: Some Common Textbook Approaches Some books introduce the concept of equation through problem solving and no doubt manage to reach a good number of students. However, to some pupils, trans lating a word problem into an equation is tantamount to translating it into a language unknown to them. In fact, even the simpler "think of a number" approach will be beyond the reach of those who cannot ac cept the representation of a number by a letter. Word problems are essential to create relevance for algebra; however, they may fail to develop meaning for equations. Another common presentation in troduces equations in terms of "open sen tences" that can be either true or false de pending on the number chosen from the "replacement set." This is then followed by the teaching of the algebraic operations re quired to solve equations. Although such an approach has the possible advantage of being very general in that it introduces si multaneously many aspects of the concept of equation (e.g., solution, nonsolution, variable), it may be doing so at the expense of clarity. Even if the students succeed in
102 citations
TL;DR: It was concluded that estrogens given during the period prior to weaning can have a feminizing effect on adult open-field behavior and that the sex difference normally observed in adult rats is dependent in part on the presence of the ovaries during a period after birth.
92 citations
TL;DR: An intracranial microinfusion system is described which can reliably deliver nl vols.
67 citations
TL;DR: The addition of α-tocopherol (vitamin E) to the culture medium at a concentration of 10 −4 was found to significantly extend the average lifespan of the rotifer Philodina.
TL;DR: In this article, it was shown that the myelinated, reward-relevant fiber of the medial forebrain bundle may synapse directly on the dopamine link, and it is hypothesized that drugs of abuse can facilitate self-stimulation by a direct action on the same neural substrate.
TL;DR: In this article, the definition of the function in the light of the revolution in mathematics is discussed, and the authors discuss the definitions of the functions in the context of the International Congress of Mathematicians.
Abstract: Since the beginning of the nineteenth century, mathematics has been undergoing a revolution. In this paper the author discusses the definition of the function in the light of this revolution. † Presented at the International Congress of Mathematicians, 1978, Helsinki, Finland.
TL;DR: In this paper, a new simple form of the extended Kalman filter, where the state consists only of the parameters to be estimated, is proposed, based on the inclusion of the computed residuals in the observation matrix of a state representation of the system, an idea first introduced in the extended least squares or Panuska's method.
Abstract: A well-known method for estimation of parameters in linear systems with correlated noise is the extended Kalman filter where the unknown parameters are estimated as a part of an enlarged state vector. To avoid the computational burden in determining the state estimates when only the parameter estimates are required, a new simple form of the extended Kalman filter, where the state consists only of the parameters to be estimated, is proposed. The algorithm is based on the inclusion of the computed residuals in the observation matrix of a state representation of the system, an idea first introduced in the so-called extended least-squares or Panuska's method. Convergence properties of the proposed algorithm are studied, and the algorithm is shown to perform a gradient-based minimization of the maximum likelihood loss function. Some special cases of the algorithm are also discussed, and an extension to an estimator for randomly varying parameters is outlined.
01 Jan 1980
TL;DR: The development of sex role behavior in children has been studied extensively in North America over the past five decades as discussed by the authors, and the importance of same-sex "identification" in the normal development of the child's personality has been discussed extensively.
Abstract: The development of sex-role behavior in children has been studied extensively in North America over the past five decades. Interest in this aspect of early childhood socialization originally derived fom psychoanalytic theories regarding the importance of same-sex “identification” in the normal development of the child’s personality. According to this position, biological factors determine the basic psychosexual “conflicts” which a male or female must face and resolve during childhood (hence Freud’s oft-quoted “anatomy is destiny”, [1961]). However, the specific form of this “conflict resolution” was thought to be determined by environmental influences and the particular experiences of the individual. The establishment of “appropriate” sex-role identification during early childhood was regarded as critical for an individual’s later sexual, psychological, and societal functioning. Further, satisfactory “resolution” of sex-role identification was viewed as a difficult and delicate process which might easily be disrupted, leading to later sexual and psychological dysfunction.
TL;DR: Pulsewidth modulation (PWM) is frequently employed with static ac power supplies to control the amplitude and harmonic content of load voltage as discussed by the authors, however, published work on the subject of PWM techniques has mainly dealt with variable-speed ac drive applications.
Abstract: Pulsewidth modulation (PWM) is frequently employed with static ac power supplies to control the amplitude and harmonic content of load voltage However, published work on the subject of PWM techniques has mainly dealt with variable-speed ac drive applications Consequently, PWM techniques compatible with constant frequency and constant (load) voltage applications, such as uninterruptible power supply (UPS) systems, have been largely ignored Several known and novel PWM techniques suitable for three-phase static UPS systems are analyzed, and attempts are made to evaluate them Optimum techniques are subsequently selected on the basis of the low-order harmonic attenuation obtained with each technique and the number of thyristor commutations (per cycle) required to implement each technique
TL;DR: In this article, charge stripping (collisional ionization) mass spectra are reported for isomeric [C5H8]- and [C3H6]- ions.
Abstract: Charge stripping (collisional ionization) mass spectra are reported for isomeric [C5H8]+˙ and [C3H6]+˙ ions. The results provide the first method for adequately quantitatively determining the structures and abundances of these species when they are generated as daughter ions. Thus, loss of H2O from the molecular ions of cyclopentanol and pentanal is shown to produce mixtures of ionized penta-1,3- and -1,4-dienes. Pent-1-en-3-ol generates [penta-1,3-diene]+˙. [C3H6]+˙ ions from ionized butane, methylpropane and 2-methylpropan-1-ol are shown to have the [propene]+˙ structure, whereas [cyclopropane]+˙ is produced from ionized tetrahydrofuran, penta-1,3-diene and pent-1-yne.
TL;DR: In this article, the authors measured the probability distributions of wind pressures acting on points or areas of low-rise building models in turbulent boundary layer flow simulating wind over open country and suburban terrains.
Abstract: Probability distributions of wind pressures acting on points or areas of low-rise building models have been measured in turbulent boundary layer flow simulating wind over open country and suburban terrains. Results show extensive positive and negative tails for high negative and positive mean pressure coefficients, respectively. Probability density functions of wind speed have also been found positively shewed at lower heights. It is shown that the Gaussian distribution underestimates the high-pressure peak factors, whereas a Weibull model fits the data adequately. Analytical expressions for the number of upcrossings of any pressure level and the extreme value distribution are presented. Comparison with experimental data shows a good agreement.
01 Jan 1980
TL;DR: In this paper, three different uniform porosities (0.0, 0.5 and 3.0% of the total surface area) have been examined in combination with openings in a wall ranging from 0 to 100% of that wall's area.
Abstract: Wind-induced internal pressures have been experimentally determined using models of low-rise buildings of different geometry and internal volume. Three different uniform porosities (0.0, 0.5 and 3.0% of the total surface area) have been examined in combination with openings in a wall ranging from 0 to 100% of that wall's area. Tests have been carried out in a simulated atmospheric boundary layer over two terrain roughnesses corresponding to open country and suburban regions. Results show that internal pressures are dynamic but their magnitudes are generally lower than those of local external pressures. For windward openings, internal pressure coefficients are generally positive with the exception of cases with high background porosity combined with small openings, when they become zero or slightly negative. The lower the background porosity, the smaller the size of the wall opening necessary to make the internal pressures insensitive to further increases of the wall opening. For all cases, high correlation has been found between those components 'oLexternal and internal pressures which participate in loading the primary structure.
TL;DR: A comparison of deaf and hearing subjects on temporal visual resolving power was conducted within a signal-detection paradigm, finding no significant differences existed on sensory sensitivity or response bias which questions some traditional assumptions about sensory compensation.
Abstract: A comparison of deaf and hearing subjects on temporal visual resolving power was conducted within a signal-detection paradigm. Subjects were required to make forced-choice judgments of a visual-flicker task under three stimulus probability conditions (0.25, 0.50, 0.75). A total of 600 trials were given each subject from which d' and Beta, indices for sensory sensitivity and response bias respectively, were computed. No significant differences existed on sensory sensitivity or response bias which questions some traditional assumptions about sensory compensation.
TL;DR: It is reported that two of four self-stimulating subjects showed no evidence of such a linkage when tested for stimulation-escape, suggesting that reward-related fibers directly link the lateral hypothalamus and ventral tegmental area.
TL;DR: Rats allowed concurrent access to intravenous heroin and intracranial self-stimulation showed facilitation of ICSS while maintaining stable self-administration of heroin, and threshold tracking allowed a reliable determination of the time-dependent effect of self- administered heroin on ICSS.
Abstract: Rats allowed concurrent access to intravenous heroin and intracranial self-stimulation (ICSS) showed facilitation of ICSS while maintaining stable self-administration of heroin. The facilitatory action of heroin on ICSS was indexed by an increase in response rates and a lowering of intensity thresholds. Both measures showed dose-dependent changes, but only threshold tracking allowed a reliable determination of the time-dependent effect of self-administered heroin on ICSS.
TL;DR: In this paper, the discharge coefficient of the flow through a lateral weir set in a rectangular channel was derived for subcritical flow in the channel upstream of the weir, and the experimental data obtained in a test flume provided a verification of the theoretical relationships between the geometric and fluid dynamic parameters of the lateral weirs flow.
Abstract: The theory of flow through a lateral conduit outlet has been adopted to derive an expression for the discharge coefficient of the flow through a lateral weir set in a rectangular channel. The theoretical expressions hold good for subcritical flow in the channel upstream of the weir. The experimental data obtained in a test flume provide a verification of the theoretical relationships between the geometric and fluid dynamic parameters of the weir flow. The proposed relationships are valid for flow through lateral weirs that can be as wide as the parent channel.
TL;DR: In this paper, a density function p such that ∥ p − f ∗ ∥ and p is the invariant density of the stochastic difference equation xn + 1 = τ(xn) + W, where W is a random variable is presented.
TL;DR: It is proposed that the rate of accumulation in the gills reflects the intrinsic activity of the toxicant and therefore a causal relationship exists between the amount of copper accumulated in gills and lethal tolerance to copper.
TL;DR: In this paper, the authors characterize the situation wherein a subspaceS of a separable Hilbert state space is holdable under the abstract linear autonomous control system, where A is the infinitesimal generator of a C0-semigroup of operators and B is a bounded linear operator mapping a Hilbert space Ω into X.
Abstract: In this paper we characterize the situation wherein a subspaceS of a separable Hilbert state space is holdable under the abstract linear autonomous control system\(\dot x = Ax + Bu\), whereA is the infinitesimal generator of aC0-semigroup of operators and whereB is a bounded linear operator mapping a Hilbert space Ω intoX. WhenS⊥∩D(A*) is dense inS⊥, it is shown that a necessary (but insufficient) condition for holdability is (1):\(A[S \cap D\left( A \right)] \subset \bar S + B\Omega\). A stronger condition than (1) is shown to be sufficient for a type of approximate holdability. In the finite dimensional setting, (1) reduces to (A, B)-invariance, which is known to be equivalent to the existence of a (bounded) linear feedback control law which achieves holdability inS. We prove that this equivalence holds in infinite dimensions as well, whenA is bounded and the linear spacesS, BΩ andS+ BΩ are closed.
TL;DR: A new general optimality principle is presented, which can be “tuned” for specific applications and considers the affects of three additional constraints, namely height, structural and node search restrictions, which lead to a number of new construction algorithms.
Abstract: The construction of optimum multiway search trees for n keys, n key weights and n+1 gap weights, is investigated. A new general optimality principle is presented, which can be "tuned" for specific applications. Moreover we consider the affects of three additional constraints, namely height, structural and node search restrictions, which lead to a number of new construction algorithms. In particular we concentrate on the construction of optimum t-ary search trees with linear and binary search within their nodes for which we obtain O(n 3 t) and O(n 3log2 t) time algorithms, respectively. Whether these algorithms are or are not optimal remains an important open problem, even in the binary case.
TL;DR: In this paper, the authors extend the replenishable resource management literature to the case of uncertainty and show that the misallocation of resources into the northern lobster fishery has been greater than was previously believed.
TL;DR: It is proposed that clearance may be associated with the repair of gill ultrastructural damage and the rapid recovery from copper intoxication in sunfish, and that clearance rate constants decreased disproportionately with increasing body weight.