Showing papers by "Concordia University published in 1985"
TL;DR: In this article, a mathematical model for obtaining the economic order quantity for an item for which the supplier permits a fixed delay in settling the amount owed to him is presented, and an example has been solved to illustrate the method.
Abstract: In this paper, mathematical models have been derived for obtaining the economic order quantity for an item for which the supplier permits a fixed delay in settling the amount owed to him. An example has been solved to illustrate the method.
1,204 citations
TL;DR: In this article, a set of beam characteristic orthogonal polynomials in the Rayleigh-Ritz method was used to obtain the natural frequencies of rectangular plates. But the results for lower modes were not as good as those obtained by other methods.
456 citations
TL;DR: In this paper, a typology of absence cultures is developed based on the degree of salience of the culture and the level of trust inherent in the psychological contract, and an example of an absence culture in transition is provided.
Abstract: The concepts of absence culture and psychological contract are invoked to explain variations in absence behavior within and between organizations and their subunits. A typology of absence cultures is developed based on the degree of salience of the culture and the level of trust inherent in the psychological contract. An example of an absence culture in transition is provided, and implications for researchers and managers are discussed.
324 citations
TL;DR: In this article, the authors explored the criteria shippers employ in the port selection process and found that decision-makers are influenced more by price and service considerations of land and ocean carriers than by perceived differences in the ports of entry and exit.
Abstract: This paper explores the criteria shippers employ in the port selection process. By focusing on the containerized traffic between the North American Mid-West and Western Europe, the factors considered by exporters and freight forwarders are examined. The findings suggest that decision-makers are influenced more by price and service considerations of land and ocean carriers than by perceived differences in the ports of entry and exit. Port infrastructures do not appear to play an important role in the routeing decisions made by an important group of independent businesses involved in the North Atlantic container trade.
319 citations
TL;DR: The sensitivity of the hippocampal Gr system to this early manipulation wanes through the first 3 weeks of life as Gr concentrations reach adult levels, suggesting that handling may directly alter the number of receptor sites per cell.
234 citations
TL;DR: Second-language acquisition research has been a hot topic in the last few decades as mentioned in this paper, with a large number of studies being carried out in the field. But the main contribution of second-language research lies not so much in what it has to say regarding the development of syllabus content or specific teaching methods, but rather in the development expectations on the part of teachers for what they and their students can accomplish.
Abstract: In fact, I am convinced that second-language research does have much to con-tribute to teaching practice in the long run. However, I believe that at present itscontribution lies not so much in what it has to say regarding the development ofsyllabus content or specific teaching methods as in what it has to say regarding thedevelopment of expectations on the part of teachers for what they and theirstudents can accomplish. Thus my title refers to two kinds of 'expectations':(1) the expectations of both teachers and researchers that second-language acquisi-tion research findings will have implications for what to teach and how to teach;(2) teachers' expectations of themselves and of their language-learning students.In this article I will very briefly review the kind of research which has been andis being carried out in second-language acquisition. I will then outline what Iconsider to be some of the most widely agreed-upon generalizations which can bedrawn from the research to date. Finally, I will discuss the ways in which I thinkit is appropriate to apply these generalizations to second-language teaching.1. SECOND-LANGUAGE ACQUISITION RESEARCH: A BRIEF REVIEWThe term 'second-language acquisition research' refers to studies which are de-signed to investigate questions about learners' use of their second language and theprocesses which underlie second-language acquisition and use. The field of researchis new—less than twenty years old if we leave out work done in the 1950s and1960s in what might be called 'preventive contrastive analysis'. Most people in thefield identify two significant papers which mark the beginning: Corder's 1967paper "The significance of learners' errors' and Selinker's 1972 paper which, in itstitle, gave a name to the object of investigation, 'Interlanguage'.Since the early 1970s, second-language acquisition research has been carriedout within a number of different theoretical frameworks and has made use ofa number of different research methods. In a 1977 review article, Hakuta andCancino summarized second-language acquisition research carried out within fourmain approaches: contrastive analysis, error analysis, performance analysis, anddiscourse analysis. Hakuta and Cancino treated these almost as a 'trial and error'series, with each new approach improving on and largely replacing the one whichpreceded it. With a few more years of hindsight, it seems that all four approachescontinue to be important to the field. Each one complements the others, ratherthan replacing them. In addition to these four, and interacting with them, areseveral approaches to second-language acquisition research which have beendeveloped in the past few years. For example, a number of recent studies are basedon a sociolinguistic approach, and there has been a great increase in the number of
227 citations
Journal Article•
TL;DR: The brain circuitry activated by two classes of abused drugs, psychomotor stimulants and opiates, is now partially understood and the current evidence suggests a shared mechanism of stimulant reward and opiate reward.
Abstract: Drugs of abuse have in common the fact that they serve as biological rewards. They presumably do so because of their ability to activate endogenous brain circuitry. By determining the brain circuitry activated by rewarding drug injections, much can be learned about the degree to which there is a common basis for the abuse liability of seemingly different drugs. The brain circuitry activated by two classes of abused drugs, psychomotor stimulants and opiates, is now partially understood; the current evidence suggests a shared mechanism of stimulant reward and opiate reward. The identified portion of the circuitry involves dopamine-containing cells of the ventral tegmental area and their fiber projections to the cells of the nucleus accumbens. Morphine activates these cells in the region of the cell bodies; it may have direct actions on receptors imbedded in the dopaminergic cell membrane, or it may act on afferent terminals that synapse on the dopaminergic cell bodies or dendrites. Cocaine and amphetamine act at the terminals of the dopaminergic fibers to nucleus accumbens and perhaps other structures. The shared activation of the dopaminergic input to nucleus accumbens accounts for the behaviorally activating and the rewarding effects of both stimulants and opiates (the opiate stimulant action is not widely known because it is usually masked by depressant actions of opiates in other, antagonistic, brain circuits). The activation of dopaminergic systems also accounts for amphetamine euphoria; it almost certainly accounts for cocaine euphoria and it probably accounts for opiate euphoria as well. Opiates and psychomotor stimulants clearly have many other actions which are not shared; nonshared actions must account for the well-known differences in the subjective effects of opiates and stimulants. One of the major nonshared actions is physical dependence. Opiates gain access to a major component of the circuitry mediating opiate physical dependence through opiate receptors in the periaqueductal gray matter. This receptor population is anatomically distinct from the population mediating the rewarding effects of opiates in nondependent animals. While both opiates and stimulants can activate (though by quite different mechanisms and at quite different loci) the dopaminergic circuitry underlying reward phenomena, only opiates activate the separate circuitry underlying dependence phenomena.(ABSTRACT TRUNCATED AT 400 WORDS)
207 citations
171 citations
TL;DR: The role of the mother and related adults in promoting sex differences in social play is understood and an understandably high degree of concordance between the social activities of young animals and the experiences from which they benefit the most is suggested.
Abstract: Publisher Summary The chapter aims to understand the role of the mother and related adults in promoting sex differences in social play. Sex differences in the social play and in the social experience of juveniles are found to be influenced by the actions of perinatal hormones. The nature of this influence appears to be in organizing the circuitry of the CNS, such that the animals are predisposed to respond to a particular stimulus in a certain way. The result of this early hormonal experience is that, males and females seem to differ in their preferred forms of social play. In the normal socialization process, both the influence of the mother and other adults and of early hormonal events seems to contribute in the same direction to the pattern of sex differences in social play. The studies discusses in this chapter also suggest an understandably high degree of concordance between the social activities of young animals and the experiences from which they benefit the most. Sex differences in social play may be seen as differences in the developmental strategies that have evolved to conform to the sex roles typical of the species. Where large sex differences in the social roles of the adults exist, there would be sex differences in developmental strategies. These developmental strategies are expressed as sex differences in preferred activities, which appear to be a function of perinatal hormones.
166 citations
TL;DR: The microstructure de l'aluminium deforme a 400°C sous des contraintes allant jusqu'a 60°C as discussed by the authors, and le epaisseur est plus grande than le diametre des sous-grains.
161 citations
TL;DR: Examination of the effects of postnatal handling of rat pups from Days 1 to 21 on the development of the intracellular, glucocorticoid receptor in the hippocampus, and pituitary transcortin, and corticoid binding globulin in plasma suggests a more efficient adrenocortical negative-feedback system in the handled animals.
Abstract: We have examined the effects of postnatal handling of rat pups from Days 1 to 21 on the development of the intracellular, glucocorticoid receptor in the hippocampus, and pituitary transcortin, and corticoid binding globulin in plasma. All animals were sacrificed 10-14h following adrenalectomy and the in vitro receptor assays were performed using 3H dexamethasone (intracellular receptors) or [3H] corticosterone (transcortin and corticoid binding globulin). Early handling resulted in a 30-40% increase in 3H dexamethasone binding (increase in Bmax with no change in Kd) in the hippocampus. In the pituitary handling was associated with a decrease in transcortin binding. There was no effect on plasma corticoid binding globulin. When tested as adults, nonhandled animals hypersecreted corticosterone following the termination of a stressor. This suggests a more efficient adrenocortical negative-feedback system in the handled animals and these data are consistent with previous work on the relationship between hippocampal glucocorticoid receptors and adrenocortical stress recovery.
TL;DR: In this paper, the effects of mass ratio, coefficient of restitution, and gap size on the free vibrations were determined by simulating motion on the digital computer, and a single unit impact damper under free and forced vibrations was studied.
TL;DR: Evidence for the existence of specific glucocorticoid receptors in the rat frontal cortex is presented, providing a possible mechanism for the influence of corticoids on catecholamine activity in the frontal cortex.
TL;DR: In this article, a doubly salient switched reluctance motor was analyzed for varying excitations at different positions of the rotor and the flux levels through different magnetic paths were obtained, and the variation of inductance with rotor position can be predicted more accurately.
Abstract: This paper describes the application of two-dimensional finite element analysis of a doubly salient switched reluctance motor. The motor has six poles on the stator and four poles on the rotor. The magnetic field patterns are determined for varying excitations at different positions of the rotor. The flux levels through different magnetic paths are obtained. The flux that passes through the rotor and stator core, the flux that flows through the interpolar air gap linking only the excited winding and the flux that links both the excited and the adjacent pole windings are clearly identified. From the results obtained, the variation of inductance with rotor position can be predicted more accurately.
TL;DR: The results of this longitudinal, prospective research programme suggest that, as a first step, peer-rated aggression and withdrawal constitute a useful broad-based behavioural index of early problems related to psychopathology.
Abstract: Summary
The results of our longitudinal, prospective research programme to date suggest that, as a first step, peer-rated aggression and withdrawal constitute a useful broad-based behavioural index of early problems related to psychopathology. The findings at this point also support our expectation that this index may serve as a fruitful criterion of vulnerability to schizophrenia in adulthood. Finally, as a screening procedure, the assessment method generated by this approach appears to be an effective means by which children in need of treatment or preventive intervention programmes may be identified.
TL;DR: In this article, the resonance Raman spectra of the single-copper blue proteins azurin plastocyanin and stellacyanin and the multicopper oxidases laccase ascorbate oxidase and ceruloplasmin are reported.
Abstract: Resonance Raman spectra of the single-copper blue proteins azurin plastocyanin and stellacyanin and the multicopper oxidases laccase ascorbate oxidase and ceruloplasmin are reported. Cryoresonance Raman observations (10-77 K) are reported for selected azurins, stellacyanin, the plastocyanins, and the laccases. Isotope studies employing /sup 63/Cu//sup 65/Cu and H/D substitution are reported for selected azurins and stellacyanin, allowing identification of modes having significant copper-ligand (Cu-L) stretch and internal ligand deformation character. Principal conclusions include the following. The only Cu-L stretching mode near 400 cm/sup -1/ is the Cu-S(Cys) stretch, and the remainder of the elementary motions near this frequency are internal ligand deformations. All the observed modes near 400 cm/sup -1/ are highly mixed, and most derive their intensity from their fractional Cu-S(Cys) stretching character. The Cu-N(His) stretching motions are best identified with the ubiquitous peak(s) near 270 cm/sup -1/, although in azurin these modes have contributions from other coordinates. Internal histidine and cysteine motions contribute to the features near 400 cm/sup -1/. This is consistent with a single resonant electronic chromophore and extremely facile vibrational dephasing or other damping processes in the electronically excited state. Temperature effects upon the spectra suggest a significant temperature-dependent structure change at the plastocyanin active site,more » and a more subtle one in azurin. It is shown that the Cu-S(Cys) stretching frequency is closely correlated to the electron-transfer exothermicity for several proteins, thereby indicating the reduction potential can be fine tuned by the effects of polypeptide backbone structure on the copper-sulfur bond distance and the copper-ligand field. 41 references.« less
Journal Article•
TL;DR: In this article, the Wilson Cycle of a late Precambrian-early Paleozoic ocean basin -the lapetus -was used to model the evolution of the Appalachians.
Abstract: Plate tectonic models for the evolution of the Appalachians involve a Wilson Cycle of a late Precambrian-early Paleozoic ocean basin - the lapetus. On one side of the lapetus lay the continent of Laurentia, which included the ancient North American landmass. Continental rifting, which initiated the formation of the lapetus in late Hadrynian/early Cambrian times, left its mark on the continental margin of Laurentia in the form of structural damage and rift-related magmatic/volcanic products, and some of these are recognizable from the south-eastern parts of Canadian Shield and the adjacent platform. These include two well-defined aulacogens, zones of step faults parallel to the ancient continental margin and possible fracture zones transverse to the ancient margin. Carbonatite complexes yielding K-Ar ages of approximately 565 Ma occur in both aulacogens. Closely associated with one of them is a prominent dike swarm of probable Hadrynian age.
TL;DR: In this paper, a novel Switch-Mode-Rectifier (SMR) structure is proposed and analyzed, which employs a high-frequency sine PWM cycloconverter to provide highfrequency ohmic isolation between the source and the load.
Abstract: A novel Switch-Mode-Rectifier (SMR) structure is proposed and analyzed in this paper The proposed converter structure employs a high-frequency sine PWM cycloconverter to provide high-frequency ohmic isolation between the source and the load Furthermore, it draws high-quality current from the ac source thus requiring only small input reactive components Consequently, the proposed converter structure exhibits high power density and has low implementation cost
TL;DR: In this article, the authors present a review of the quantum-mechanical aspects of the relativistic quantum mechanics and quantum space-time program, with some mention of work done also on the quantization of space time.
Abstract: The deeper problem in question here can be identified in the following anomaly: The theory of relativity and its associated notion of space-time is based upon the concept of events involving classical test particles and on the relationship between events. The particles described by quantum mechanics are subject to the uncertainty principle and yet one tries to describe relationships between events involving quantum particles against the same classically derived space-time background. It is the aim of this review to decribe some recent work which attempts to resolve this anomaly. We mainly dwell on the quantum-mechanical aspects of this programme, with some mention of work done also on the quantization of space-time. In brief, the stochastic quantum mechanics and quantum space-time programme attempts to do the following: First a theory of localization for quantum systems on phase space is developed. The relativistic invariance of the phase space volume element is then exploited to obtain a version of single-particle quantum mechanics on phase space. This theory is free of the old problems of relativistic quantum mechanics and is a theory which admits a conserved probability current. Using such a notion of a single relativistic quantum particle, an attempt is then made to build a quantum space-time. (orig./HSI).
TL;DR: In this paper, practical computational techniques are described to determine the Galois group of a polynomial over the rationals, and each transitive permutation group of degree 3 to 7 is realized as a Galois groups over rationals.
TL;DR: In this article, the authors show that the strength and ductility of the hot worked product can be improved by refinement of the grains and by the retention of the deformation substructure if desired.
Abstract: After hot deformation, during either holding until the next pass or final cooling, static recovery takes place followed by static recrystallization in certain cases. The rate of classical static recrystallization depends on the accumulated strain energy and the temperature. The rate of post dynamic recrystallization depends on the above factors and on the occurrence of dynamic recrystallization during prior straining. The hot ductility is enhanced by increasing the ease of both dynamic recovery, which retards nucleation of intergranular cracks, and dynamic recrystallization, which hinders fissure growth by moving grain boundaries away from them. The presence of solutes and precipitates reduces workability by hindering dynamic softening but the static softening associated with multistage processing improves it. The strength and ductility of the hot worked product can be improved by refinement of the grains and by the retention of the deformation substructure if desired.
TL;DR: In this paper, an estimate of a type of regression that converges with O(nC−(2s−1)/4s) in probability and O( n−(n−( 2s− 1/4s logn) almost completely in probability is given.
Abstract: In the paper we estimate a regressionm(x)=E {Y|X=x} from a sequence of independent observations (X1,Y1),…, (Xn, Yn) of a pair (X, Y) of random variables. We examine an estimate of a type\({{\hat m\left( x \right) = \sum\limits_{j = 1}^n {Y_{j\varphi N} } \left( {x,X_j } \right)} \mathord{\left/ {\vphantom {{\hat m\left( x \right) = \sum\limits_{j = 1}^n {Y_{j\varphi N} } \left( {x,X_j } \right)} {\sum\limits_{j = 1}^n {\varphi _N } \left( {x,X_j } \right)}}} \right. \kern-
ulldelimiterspace} {\sum\limits_{j = 1}^n {\varphi _N } \left( {x,X_j } \right)}}\), whereN depends onn andϕN is Dirichlet kernel and the kernel associated with the hermite series. Assuming, that E|Y|<∞ and |Y|≦γ≦∞, we give condition for\(\hat m\left( x \right)\) to converge tom(x) at almost allx, provided thatX has a density. if the regression hass derivatives, then\(\hat m\left( x \right)\) converges tom(x) as rapidly asO(nC−(2s−1)/4s) in probability andO(n−(2s−1)/4s logn) almost completely.
TL;DR: In Canada, as in many other countries that have adopted R&D tax credits and allowances, there has been considerable controversy over their effectiveness in increasing company-financed research and development as discussed by the authors.
TL;DR: A heuristic method is proposed for determining the economic maintenance frequency of each machine and an example is given to illustrate the method.
Abstract: This paper deals with the problem of determining economic maintenance frequency for a group of machines. The operating cost for each machine is assumed to increase with time since the last maintenance work carried out on the machine. The cost of carrying out maintenance work is known and assumed constant. A fixed cost is incurred whenever maintenance work is carried out, and this fixed cost is assumed to be independent of the number of machines on which maintenance work is carried out. The total cost of the system is given by the sum of maintenance and operating costs for all the machines. A heuristic method is proposed for determining the economic maintenance frequency of each machine. An example is given to illustrate the method.
TL;DR: In this article, an isotropic-kinematic hardening rule for sand is proposed applicable to both monotonic and cyclic loading conditions, based on the theory of bounding surface plasticity incorporating, as in the previous studies, a non-associated flow rule.
TL;DR: These findings suggest that, for selected Type A men, exaggerated psychophysiological reactivity occurs reliably when monitored with multiple indices, appears insensitive to mere passage of time, and can be uniformly elicited by a variety of tasks.
TL;DR: A distributed rule-based system for automatic speech recognition is described and experiments on the automatic segmentation and recognition of phrases, made of connected letters and digits, are described and discussed.
Abstract: A distributed rule-based system for automatic speech recognition is described. Acoustic property extraction and feature hypothesization are performed by the application of sequences of operators. These sequences, called plans, are executed by cooperative expert programs. Experimental results on the automatic segmentation and recognition of phrases, made of connected letters and digits, are described and discussed.
TL;DR: This article investigated the role played by linguistic universals in second language acquisition and found that unmarked forms are acquired before marked ones, consistent with the predictions made by the theory of markedness and the property of adjacency which is crucial for case assignment.
Abstract: The aim of this paper is to demonstrate the role played by linguistic universals in second language acquisition. Research reported here focuses on the acquisition of dative structures and dative questions in a passive context in English by French and Inuit (Eskimo) students. Data were also elicited from native English-speaking students to serve as the norm. The data are interpreted within the theory of markedness and core grammar, as well as Case theory. The results of the testing, showing that unmarked forms are acquired before marked ones, are consistent with the predictions made by the theory of markedness and the property of adjacency which is crucial for Case assignment.