Showing papers by "University of Toronto published in 1981"
TL;DR: It was shown that the ADR probability scale has consensual, content, and concurrent validity and may be applicable to postmarketing drug surveillance.
Abstract: The estimation of the probability that a drug caused an adverse clinical event is usually based on clinical judgment. Lack of a method for establishing causality generates large between-raters and within-raters variability in assessment. Using the conventional categories and definitions of definite, probable, possible, and doubtful adverse drug reactions (ADRs), the between-raters agreement of two physicians and four pharmacists who independently assessed 63 randomly selected alleged ADRs was 38% to 63%, kappa (k, a chance-corrected index of agreement) varied from 0.21 to 0.40, and the intraclass correlation coefficient of reliability (R[est]) was 0.49. Six (testing) and 22 wk (retesting) later the same observers independently reanalyzed the 63 cases by assigning a weighted score (ADR probability scale) to each of the components that must be considered in establishing causal associations between drug(s) and adverse events (e.g., temporal sequence). The cases were randomized to minimize the influence of learning. The event was assigned a probability category from the total score. The between-raters reliability (range: percent agreement = 83% to 92%; κ = 0.69 to 0.86; r = 0.91 to 0.95; R(est) = 0.92) and within-raters reliability (range: percent agreement = 80% to 97%; κ = 0.64 to 0.95; r = 0.91 to 0.98) improved (p < 0.001). The between-raters reliability was maintained on retesting (range: r = 0.84 to 0.94; R(est) = 0.87). The between-raters reliability of three attending physicians who independently assessed 28 other prospectively collected cases of alleged ADRs was very high (range: r = 0.76 to 0.87; R(est) = 0.80). It was also shown that the ADR probability scale has consensual, content, and concurrent validity. This systematic method offers a sensitive way to monitor ADRs and may be applicable to postmarketing drug surveillance.
Clinical Pharmacology and Therapeutics (1981) 30, 239–245; doi:10.1038/clpt.1981.154
9,840 citations
TL;DR: In this paper, it is shown that principal component analysis (PCA) is a powerful tool for coping with structural instability in dynamic systems, and it is proposed that the first step in model reduction is to apply the mechanics of minimal realization using these working subspaces.
Abstract: Kalman's minimal realization theory involves geometric objects (controllable, unobservable subspaces) which are subject to structural instability. Specifically, arbitrarily small perturbations in a model may cause a change in the dimensions of the associated subspaces. This situation is manifested in computational difficulties which arise in attempts to apply textbook algorithms for computing a minimal realization. Structural instability associated with geometric theories is not unique to control; it arises in the theory of linear equations as well. In this setting, the computational problems have been studied for decades and excellent tools have been developed for coping with the situation. One of the main goals of this paper is to call attention to principal component analysis (Hotelling, 1933), and an algorithm (Golub and Reinsch, 1970) for computing the singular value decompositon of a matrix. Together they form a powerful tool for coping with structural instability in dynamic systems. As developed in this paper, principal component analysis is a technique for analyzing signals. (Singular value decomposition provides the computational machinery.) For this reason, Kalman's minimal realization theory is recast in terms of responses to injected signals. Application of the signal analysis to controllability and observability leads to a coordinate system in which the "internally balanced" model has special properties. For asymptotically stable systems, this yields working approximations of X_{c}, X_{\bar{o}} , the controllable and unobservable subspaces. It is proposed that a natural first step in model reduction is to apply the mechanics of minimal realization using these working subspaces.
5,134 citations
TL;DR: The effect of different foods on the blood glucose levels was fed individually to groups of 5 to 10 healthy fasting volunteers, and a significant negative relationship was seen between fat and protein and postprandial glucose rise but not with fiber or sugar content.
3,336 citations
TL;DR: It is concluded that the atrial extract contained an extremely powerful inhibitor of renal tubular NaCl re absorption, which caused a rapid, more than 30-fold increase of sodium and chloride excretions, while urine volume and potassium excretion doubled.
3,051 citations
TL;DR: In this paper, observations on N cross-section units at T time points are used to estimate a simple statistical model involving an autoregressive process with an additive term specific to the unit.
Abstract: Observations on N cross-section units at T time points are used to estimate a simple statistical model involving an autoregressive process with an additive term specific to the unit. Different assumptions about the initial conditions are (a) initial state fixed, (b) initial state random, (c) the unobserved individual effect independent of the unobserved dynamic process with the initial value fixed, and (d) the unobserved individual effect independent of the unobserved dynamic process with initial value random. Asymptotic properties of the maximum likelihood and “covariance” estimators are obtained when T → ∞ and when N → ∞. The relationship between the pseudo and conditional maximum likelihood estimators is clarified. A simple consistent estimator that is independent of the initial conditions and the way in which T or N → ∞ is also suggested.
2,372 citations
TL;DR: In this article, it was shown that the general nature of deviations from uniformity in the spectrum of a complicated nucleus is essentially the same in all regions of the spectrum and over the entire Periodic Table.
Abstract: It now appears that the general nature of the deviations from uniformity in the spectrum of a complicated nucleus is essentially the same in all regions of the spectrum and over the entire Periodic Table. This behavior, moreover, is describable in terms of standard Hamiltonian ensembles which could be generated on the basis of simple information-theory concepts, and which give also a good account of fluctuation phenomena of other kinds and, apparently, in other many-body systems besides nuclei. The main departures from simple behavior are ascribable to the moderation of the level repulsion by effects due to symmetries and collectivities, for the description of which more complicated ensembles are called for. One purpose of this review is to give a self-contained account of the theory, using methods: sometimes approximate: which are consonant with the usual theory of stochastic processes. Another purpose is to give a proper foundation for the use of ensemble theory, to make clear the origin of the simplicities in the observable fluctuations, and to derive other general fluctuation results. In comparing theory and experiment, the authors give an analysis of much of the nuclear-energy-level data, as well as an extended discussion of observable effects in nuclear transitionsmore » and reactions and in the low-temperature thermodynamics of aggregates of small metallic particles.« less
1,626 citations
TL;DR: It is shown that this family of graphs can be uniquely represented by a tree where the leaves of the tree correspond to the vertices of the graph.
872 citations
TL;DR: Two groups of patients who had Legg-Calvé-Perthes disease were studied and each hip in both study groups could be placed into one of five classes of deformity based on its radiographic appearance at maturity.
Abstract: Two groups of patients who had Legg-Calve-Perthes disease were studied. The first group of patients consisted of eighty-eight patients (ninety-nine affected hips) followed in three hospitals for an average of forty years. The second group consisted of sixty-eight patients (seventy-two affected hips), all of whose radiographs from the onset of disease to maturity were available and all of whom had been treated in one hospital. The patients in this second group were followed for an average of thirty years. Each hip in both study groups could be placed into one of five classes of deformity based on its radiographic appearance at maturity. Each class showed a characteristic pattern of involvement during the active stages of the disease and had a specific long-term clinical and radiographic course. The clinical and radiographic course of an involved hip subsequent to childhood was related to the type of congruency that existed between the femoral head and acetabulum. Three types of congruency were recognized: (1) spherical congruency (Class-I and II hips) - in hips in this category arthritis does not develop; (2) aspherical congruency (Class-III and IV hips) - mild to moderate arthritis develops in late adulthood in these hips; and (3) aspherical incongruency (Class-V hips) - severe arthritis develops before the age of fifty years in these hips.
725 citations
TL;DR: Results indicate that endothelial blood-brain barrier characteristics develop in response to some aspect of the neural environment, as well as abdominal vessels vascularizing grafted mesodermal tissue, which were devoid of barrier characteristics.
649 citations
TL;DR: In this article, the susceptibility to social desirability response bias of four alternative methods of measuring the importance of job and organizational characteristics is examined. Data were collected from 86 gr....
Abstract: The susceptibility to social desirability response bias of four alternative methods of measuring the importance of job and organizational characteristics is examined. Data were collected from 86 gr...
459 citations
TL;DR: The hypothesis that sentence production is organized into independent positional and functional stages is tested and it was found that sound misordering errors tend to create words and that word errors, such as substitutions and misorderings, tend to involve similar sounding words.
TL;DR: This overview is designed to put these articles into a broader perspective by analyzing the major issues of identification, forecasting, and strategy formulation encountered in any meaningful application of the product life cycle.
Abstract: Each of the articles in this special section makes a distinctive contribution to the long-standing controversy over the managerial value of the product life cycle concept. This overview is designed...
TL;DR: In this article, the authors introduce the concept of an ideal (superconducting) current return plane placed below the ground surface at a complex distance p equal to the complex penetration depth for plane waves.
Abstract: For modelling current return in homogeneous ground, the paper introduces the concept of an ideal (superconducting) current return plane placed below the ground surface at a complex distance p equal to the complex penetration depth for plane waves. This "complex" plane appears as a mirroring surface, so that conductor images can be used to derive very simple formulae for self and mutual impedances under ground return conditions. Such equations, without proofs, were originally proposed by Dubanton and published by Gary.1 In this paper, plausibility arguments serve to initially justify the procedure, then the equations are analytically related to those of Carson and, finally, the errors, which in most cases are less than a few percent, are numerically evaluated. The ideal return plane at complex depth can also be used for multi-layer earth return.
TL;DR: In this paper, an analytical and experimental investigation of a windmill which utilizes a harmonically oscillating wing to extract wind energy is described. Butler et al. developed a theoretical analysis utilizing unsteady-wing aerodynamics from aeroelasticity and guided the design of a working model for wind-tunnel experiments.
Abstract: This article describes an analytical and experimental investigation of a windmill which utilizes a harmonically oscillating wing to extract wind energy. In particular, the wing's span is horizontally aligned and the airfoil is a chordwise-rigid symmetrical section. The whole wing oscillates in vertical translation and angle-of-attack, with prescribed phasing between the two motions. A theoretical analysis was developed utilizing unsteady-wing aerodynamics from aeroelasticity and the results guided the design of a working model for wind-tunnel experiments. For the cases tested, theory and experiment compared favorably, and showed the wingmill to be capable of efficiencies comparable to rotary designs.
TL;DR: Intracellular recordings from pairs of neurons in slices of rat hippocampus directly demonstrate electrotonic coupling between neurons in the mammalian brain and indicate that some fast prepotentials are coupling potentials.
Abstract: Intracellular recordings from pairs of neurons in slices of rat hippocampus directly demonstrated electronic coupling between CA3 pyramidal cells. When two neurons were impaled simultaneously (as verified by subsequent double staining with horseradish peroxidase), current pulses injected into one cell caused voltage changes in other cells. These interactions were bidirectional. Fast prepotentials, historically thought to represent spike activity in dendrites, resulted from action potentials in other electronically coupled pyramidal cells. These data directly demonstrate electrotonic coupling between neurons in the mammalian brain and indicate that some fast prepotentials are coupling potentials. Coupling between pyramidal cells could mediate synchronization of normal rhythmic activity and of burst discharges during seizures.
TL;DR: The historical and technical background of MVL, and areas of present and future application are described, intended to serve as a tutorial for the nonspecialist.
Abstract: Advances in multiple-valued logic (MVL) have been inspired, in large part, by advances in integrated circuit technology Multiple-valued logic has matured to the point where four-valued logic is now part of commercially available VLSI IC's Besides reduction in chip area, MVL offers other benefits such as the potential for circuit test This paper describes the historical and technical background of MVL, and areas of present and future application It is intended, as well, to serve as a tutorial for the nonspecialist
TL;DR: Nulliparous animals were found to be more fearful than parturient animals: they had longer emergence latencies, they ambulated less in the open field, they crossed proportionately fewer central, as opposed to peripheral, squares in the field, and they were more inclined to flee from the intruder.
TL;DR: In this article, the authors analyzed the professional commitment of Canadian Chartered Accountants who are partners, managers (supervisors) and other staff CAs in public practice in relation to organizational commitment, professional-organizational conflict, satisfaction with income and organizational level.
Abstract: This study analyzes the professional commitment of Canadian Chartered Accountants who are partners, managers (supervisors) and other staff CAs in public practice. This commitment is examined in relation to organizational commitment, professional-organizational conflict, satisfaction with income and organizational level. The commitment to organization is shown to be the most powerful predictor of CAs' professional commitment in all organizational levels. At the same time, professional-organizational conflict has a negative impact on professional commitment, and satisfaction with income has a positive influence on such a commitment.
TL;DR: In this article, the authors present a review of the state-of-the-art in fine-particle magnetism, focusing on domain structure transitions, pseudo-single-domain mechanisms, diagnostic tests of domain structure, chemical, detrital, thermal and viscous magnetization processes, and magnetostatic interaction.
TL;DR: In this paper, the authors studied the relation between the distribution of the system state embedded at those moments and the steady-state (or random point) distribution, and showed that if a job class belongs to an open subchain, the state distributions at input pomts, output points, and random points are identical, and if the job classes belong to a closed sub chain, the distribution at input and output points ts the same as the steady state distribution of a network with one less job in that subchain.
Abstract: Queuing networks are studied at selected points in the steady state, namely, at the moments when jobs of a given class arrive into a given node (either from the outside or from other nodes) and at the moments when jobs of a given class leave a given node (either for the outside or for other nodes). The processes defined by these points are known to be, in general, non-Potsson, interdependent, and serially correlated; therefore the relation between the distribution of the system state embedded at those moments and the steady-state (or random point) distribution is not obvious a priori. For a large class of networks having product-form equihbrium distribnttons it is shown that (a) if the given job class belongs to an open subchain, the state distributions at input pomts, output points, and random points are identical, and (b) if the job class belongs to a closed subchain, the distribution at input and output points ts the same as the steady-state distribution of a network with one less job in that subchain.
TL;DR: Commercial fluid used for peritoneal lavage in peritonitis and inPeritoneal dialysis suppressed the activity of peripheral blood leukocytes as measured by chemiluminescence, phagocytosis, and bacterial killing.
Abstract: Commercial fluid used for peritoneal lavage in peritonitis and in peritoneal dialysis suppressed the activity of peripheral blood leukocytes as measured by chemiluminescence, phagocytosis, and bacterial killing. Suppression was found to be due to the low pH and high osmolality of the fluid. The pH was adjusted to noninhibitory levels in vivo within 30 min, whereas osmolality changes were less rapid and remained at inhibitory levels for fluids of high dextrose concentration (4.25%). Chemiluminescence was the most sensitive assay for inhibitory effects of pH and osmolality, as well as for urea and heparin. The metabolic waste product urea at levels normally found in dialysate and heparin at concentrations routinely added to fluid inhibited only chemiluminescence, whereas creatinine and added insulin were not inhibitory. High fluid volume also resulted in a decrease in efficiency of bacterial killing. These results suggest some changes to be made in the treatment of peritonitis and in peritoneal dialysis.
TL;DR: This article found that the self-perception account of attitude expression holds primarily for individuals with poorly defined prior attitudes, but not high-consistency subjects, with well-defined attitudes, expressed postmanipulation environmentalist attitudes that were congruent with the proor anti-ecology behaviors made salient by questionnaire manipulation.
Abstract: Subjects with well-defined or poorly defined prior attitudes toward being an environmentalist/conservationist were identified by assessing the structural consistency between the affective and cognitive components of their attitudes. After subjects completed one of two versions of a questionnaire designed to make salient either past pro-ecology or past anti-ecology behaviors, their final attitudes were assessed. The hypothesis that the self-perception account of attitude expression holds primarily for individuals with poorly defined prior attitudes was supported: Low-consistency subjects, with presumably poorly defined attitudes, but not highconsistency subjects, with well-defined attitudes, expressed postmanipulation environmentalist attitudes that were congruent with the proor anti-ecology behaviors made salient by the questionnaire manipulation. The additional finding that high-consistency (vs. low-consistency) subjects' beliefs on five ecology-related issues were more highly intercorrelated supported the assumption that the consistency construct appropriately indexes the degree to which individuals possess well-defined attitudes. A comparison of theory and research on self-schemata with research on the affective-cognitive consistency variable suggested that the latter may be a useful measure of attitude schematicity.
TL;DR: It was concluded that Paneth cells originate in position 5 or above and then migrate downward, consistent with a stem-cell zone hypothesis, which proposes that stem cells in positions 1-4 receive no inducement to differentiate.
Abstract: The restriction of Paneth cell formation to the top of the Paneth cell distribution in the adult was suggested to be due either to the existence of a stem-cell zone or to the influence of a Paneth cell population-density gradient (Bjerkness and Cheng, 1981) To distinguish between the two possible mechanisms, the development of the Paneth cell distribution in neonatal mice (0-10 days old) was studied If restricted formation were due to the presence of a population-density gradient of Paneth cells, then in neonatal animals, in the absence of a Paneth cell population-density gradient, Paneth cell formation would occur throughout the crypt base If, on the other hand, restricted formation were due to the presence of a stem-cell zone, and if this mechanism were operative in the newborn, Paneth cell formation in the newborn would be restricted to the region above the stem-cell zone The position of each Paneth cell within the crypt, and the size of its largest granule, were recorded On day 0, Paneth cells were present, but crypts were poorly developed and positional assignment was not possible On day 1, immature crypts developed All Paneth cells found in immature crypts on day 1 were at the crypt-surface junction (approximately position 5) On day 2, most Paneth cells were at the crypt-surface junction Thereafter, Paneth cells began to appear at lower positions On day 3, there were 15 times more Paneth cells in position 5 than in position 1 On day 4, there were still three times more Paneth cells in position 5 than in position 1 With age, the proportion of Paneth cells in position 1 increased while that in position 5 decreased On day 10 there were more Paneth cells in position 1 than in 5 At all time intervals, granules of Paneth cells in position 1 were significantly larger than those in position 5, indicating that Paneth cells in position 1 were older than those in position 5 It was concluded that in the neonate, before the establishment of a Paneth cell population-density gradient, Paneth cell formation was restricted to positions 5 and above This supports the existence of a stem-cell zone, not a Paneth cell population-density gradient, as the underlying mechanism of restricted Paneth cell formation in the adult
TL;DR: The fatty acid content of fetal tissues was utilized to estimate essential fatty acid accretion during intrauterine growth and it was concluded that some 70 and 78% of these net whole body accretion rates for essential fatty acids represent omega-6 and omega-3 fatty Acid accretion in the adipose organs.
TL;DR: In this article, the authors describe a practical procedure for generating a large class of functional forms for dynamic factor demand functions that can be used to test and apply the adjustment-cost theory of the firm.
Abstract: A large body of empirical studies of factor demand systems (Christensen, Jorgenson and Lau (1973), Berndt and Christensen (1973), Fuss and McFadden (1978)) is based on the assumption of instantaneous adjustment by firms to prevailing prices. An exhaustive set of integrability conditions derived from the theory of static profit maximization is applied to guide the specification of functional forms and to motivate meaningful hypotheses to be tested or maintained. In contrast, such a sound theoretical basis is lacking for most of the empirical literature on dynamic factor demand (investment and employment) models. For example, Jorgenson (1965) appends an ad hoc lag structure to a theory of static profit maximization to generate an investment demand function. The recent developments in the adjustmentcost model of the firm (Lucas (1967), Treadway (1969), (1971), Mortensen (1973)) have provided a consistent dynamic theoretical framework for the determination of all inputs and outputs. Yet there still remains a gap between the theoretical model and most econometric factor demand models (Schramm (1970), Nadiri and Rosen (1969), Brechling (1975)); the latter maintain a flexible accelerator adjustment with constant adjustment coefficients while the theory implies that the flexible accelerator is generally optimal only locally in a neighbourhood of the steady state and that the adjustment coefficients generally depend on exogenous variables. (See Treadway (1974).) The studies cited also fail to relate satisfactorily the hypothesized adjustment matrices to the specified technologies. They thereby overlook some of the testable properties of the theory. Only Berndt, Fuss and Waverman (1977) have estimated a model that is fully consistent with the adjustment-cost theory. The objective of this paper is to describe a practical procedure for generating a large class of functional forms for dynamic factor demand functions that can be used to test and apply the adjustment-cost theory of the firm. Three limitations of the approach adopted by Berndt, Fuss and Waverman may be noted. First, their approach is practical only when there is a single quasi-fixed stock (or (footnote 6) perhaps at most when there are two quasi-fixed stocks). Second, the flexible accelerator is the only adjustment mechanism that can follow from their approach. Finally, they assume that firms expect current prices to persist indefinitely. In contrast the procedure developed below is applicable to any number of quasi-fixed stocks and is capable of generating a richer class of dynamic adjustment mechanisms, e.g. the hump-shaped lag distributions that have been estimated in the empirical literature on investment (Evans (1969; pp. 95-105)) and which have been modelled by various ad hoc lag structures such as the Almon, Pascal and rational distributed lags. However, the assumption of static expectations, common in the adjustment-cost literature, is maintained.
TL;DR: A partition assay is described which allows a rapid determination of juvenile hormone release by insect corpora allata by quantitatively extracting into an isooctane phase, whereas precursor methyl-labeled l-methionine remains in the incubation medium.
TL;DR: By immunohistochemistry, bombesin, calcitonin and leu-enkephalin was localized in endocrine cells of human lungs from various age groups and it is suggested that at least 3 different peptide containingendocrine cells may be present in human lung.
Abstract: By immunohistochemistry, bombesin, calcitonin and leu-enkephalin was localized in endocrine cells of human lungs from various age groups. It is suggested that at least 3 different peptide containing endocrine cells may be present in human lung.
TL;DR: Proper screening and therapy are essential in all girls with menorrhagia, and conventional methods of hormonal control are only partially effective in these special cases.
TL;DR: Heart, liver, gonad, gut and visceral fat increased during recovery growth in a manner suggestive of overcompensation in response to former food deprivation, and Gut, skin and carcase dry weights were less in the control and in the 14.5% weight loss groups following recovery growth, indicating that the effects of slow growth resulting from limited rations resemble those of severe starvation more than those of limited starvation.
Abstract: Fingerling rainbow trout (6.9 to 11.6 cm fork length) maintained at 12° C were either: fed restricted rations (3% of dry body weight/day) for 16 weeks, or starved for 3 weeks (14.5% weight loss), or for 13 weeks (32.5% weight loss). Whole body wet weights and dry weights (as % of wet weight), and wet and dry weights of tissues (heart, spleen, liver, skin, gonad, gut, visceral fat, and ‘carcase’) resulting from these treatments were compared to corresponding weights of an ‘initial sample’. Visceral fat was completely utilized during both short and long-term starvation and gut was significantly reduced in the extended starvation group.
During subsequent recovery growth on full rations, following food deprivation, fish grew at approximately the same rate as fully-fed controls, which had not suffered food deprivation, as regards body wet weight and condition (K), but tended to surpass controls in % dry weight.
Heart, liver, gonad, gut and visceral fat also increased during recovery growth in a manner suggestive of overcompensation in response to former food deprivation. Gut, skin and carcase dry weights were less in the control, and in the 14.5% weight loss groups following recovery growth than in those in 3% rations and in the severely starved group, indicating that the effects of slow growth resulting from limited rations resemble those of severe starvation more than those of limited starvation.