Showing papers by "Université de Montréal published in 1979"
TL;DR: In this article, the authors considered linear systems with delays in state and/or control variables and designed a feedback law which yields a finite spectrum of the closed-loop system, located at an arbitrarily preassigned set of n points in the complex plane.
Abstract: In this paper linear systems with delays in state and/or control variables are considered. The objective is to design a feedback law which yields a finite spectrum of the closed-loop system, located at an arbitrarily preassigned set of n points in the complex plane. It is shown that in case of systems with delays in control only the problem is solvable if and only if some function space controllability criterion is met. The solution is then easily obtainable by standard spectrum assignment methods, while the resulting feedback law involves integrals over the past control. In case of delays in state variables it is shown that a technique based on the finite Laplace transform, related to a recent work on function space controllability, leads to a constructive design procedure. The resulting feedback consists of proportional and (finite interval) integral terms over present and past values of state variables. Some indications on how to combine these results in case of systems including both state and control delays are given. Sensitivity of the design to parameter variations is briefly analyzed.
1,072 citations
TL;DR: Neuraminidase activity was considerably reduced in cultured fibroblasts of patients with mucolipidosis types I, II, and III and in cultured Fibroblast and leucocyte neuraminidases showed maximum activity between pH 4.2 and 4.4.
816 citations
265 citations
TL;DR: In view of the anatomical data demonstrating a relative sparsity of monoamine nerve terminals in cerebral cortex, the strong inhibition induced by DA, NA or 5-HT may have reflected slow inactivation of the biogenic amines, and could also be indicative of underlying mechanisms of action dependent on metabolic changes.
245 citations
228 citations
TL;DR: The one-hour blood-xylose test emerged as a simple and valuable test in the diagnosis of C.M.P.I. protein intolerance, and in all patients but one it dropped below 25 mg/dl.
216 citations
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TL;DR: The dogit model as discussed by the authors allows the choice among specific pairs of alternatives to be consistent with the independence from irrelevant alternatives axiom, as in a logit model, but it simultaneously allows the choices among other pairs not to be.
Abstract: This paper presents the dogit model. That model is flexible enough to permit the choice among specific pairs of alternatives to be consistent with the independence from irrelevant alternatives axiom, as in a logit model, but it simultaneously allows the choice among other pairs not to be. Dogit parameters add an “income effect” to the “substitution effect” already built into the logit model; alternatively, they allow for the joint presence of compulsive and discretionary elements in consumer behavior, or for the identification of captive markets. Eventual estimation of the values of the parameters of the dogit model appears simpler than for the probit model.
209 citations
TL;DR: A new family of shortest-route methods are presented, which reduce an upper bound on running time, and make empirical comparisons for a certain class of networks, and allow for exploitation of structure by pruning arcs and/or nodes.
Abstract: We present a new family of shortest-route methods, which reduce an upper bound on running time, and make empirical comparisons for a certain class of networks. These methods also allow for exploitation of structure by pruning arcs and/or nodes.
209 citations
TL;DR: In this article, the crystal structure of poly(trimethylene terephthalate) was determined by a combination of electron diffraction, X-ray diffraction and packing analyses.
160 citations
TL;DR: In this article, the chemical and physical properties of a natural (1→3)-β-d -glucan found in Euglena gracilis and curdlan were compared to each other and it was concluded that this system is a "native-regenerated" pair just as the well known "native cellulose-generated cellulose" system.
136 citations
TL;DR: This selective reaction, which involved approximately 1000 neurons on each side of the third ventricle, was unaltered by concomitant administration of 10 (-3) M non-radioactive norepinephrine, and was absent after intraventricular injection of 10(-5) or 10(-4) M tritiated nore Alpinephrine.
TL;DR: In this paper, the authors used a surface wave propagation with a surfatron to obtain high stability and repeatability with an argon flow of 2-17 l/min with a typical electron density of 3 × 1014 electrons/cm3.
TL;DR: A Grundy n-coloring of a finite graph is a coloring of the points of the graph with the non-negative integers smaller than n such that each point is adjacent to some point of each smaller color but to none of the same color.
TL;DR: An analysis of the familial aggregation of blood pressure was conducted to provide estimates of the role of genes and household environment in determining the phenotypic resemblance between biologically related family members.
Abstract: An analysis of the familial aggregation of blood pressure (BP) was conducted to provide estimates of the role of genes and household environment in determining the phenotypic resemblance between biologically related family members. The biological model used for this analysis parameterizes the correlations between family members into the contributions of genetic and environmental variability shared within and across generations. Hypothesis testing about different parameters in the model suggests that shared environment explains larger fractions of the parent-natural child and the full sib correlations for diastolic BP than for systolic BP. For diastolic BP, children in a household share the effects of common environment in addition to the effects which they share with their parents. Dependence of the degree of resemblance between household members on the effects of environmental factors shared within and a-ross generations is not explained by the variability of length of cohabitation among individuals.
TL;DR: In the cone pedicules, the digitations of horizontal cell process lateral to the synaptic ribbon disappear after dark adaptation, correlated with the loss of color opponency and cone function shown in ganglion cell recordings in isolated retinas.
Abstract: In the cone pedicules, the digitations of horizontal cell process lateral to the synaptic ribbon disappear after dark adaptation. This disappearance is correlated with the loss of color opponency and cone function shown in ganglion cell recordings in isolated retinas. Cone function and color-opponent responses are restored by reapplying background light.
TL;DR: The results were much better than expected, in fact, the excellent, very good, and good results equaled 93% of the authors' cases.
Abstract: De janvier 1960 a janvier 1974, 180 cas d'osteomyelite chronique furent traites par un meme chirurgien au sein de l'unite d'infection de l'Hopital Notre-Dame de Montreal. De ces cas, 71.4% furent traites par mise a plat simple suivie de fermeture secondaire ou de greffe cutanee d'epaisseur moyenne. Dix cas (5.4%) durent subir une amputation. Cependant dans 39 cas deux techniques semblables d'excision-greffe a ciel ouvert furent utilisees. L'origine de l'infection etait surtout traumatique et le microbe le plus souvent en cause, le staphylocoque, surtout sensible a la cloxacilline et a la dicloxacilline. Les resultats depasserent nos previsions, amenant une guerison plus qu'adequate dans 93% des cas. Deux recidives tardives furent enregistrees, 17 ans et 4 ans apres la fin du traitement.
TL;DR: Plasma catecholamine levels were determined in 26 cases of uncomplicated myocardial infarction within 24 hours of onset of acute chest pain and were significantly higher when determined while patients presented ventricular ectopic beats or ventricular tachycardia.
TL;DR: This paper refine a branch-and-bound algorithm proposed by Hoang and compares the resuling algorithm to an algorithm developed by Boyce et al.
Abstract: In this paper, we present exact and approximate algorithms for the problem of optimal network design, which was first studied by Ridley [15], Stairs [17] and Scott [16], among others. Given a network, the problem consists in selecting a subset of links that minimizes the sum of shortest routes between all nodes subject to a budget constraint. Congestion effects are not considered. First, we refine a branch-and-bound algorithm proposed by Hoang [7] and we compare the resuling algorithm to an algorithm developed by Boyce et al. [1]. Our conclusion is that these exact algorithms perform adequately on medium size problems; however, for larger problems, approximate methods based on heuristic approaches are necessary. We then introduce two new heuristic approaches and test their computational efficiency as well as that of two other already known heuristics. The new heuristics presented produce excellent results. Finally, we consider more general versions of the problem.
TL;DR: Results are consistent with the concept that PRL increases synthesis of the 1 series of prostaglandins by mobilizing DHGL and provide further evidence that zinc may play a role in some actions of PRL.
Abstract: Ovine PRL at low concentrations potentiated pressor responses to norepinephrine and angiotensin in an isolated perfused rat mesenteric vascular preparation. Higher concentrations inhibited these pressor responses. Pressor responses to potassium which depend on extracellular calcium entry into the muscle were unaffected by PRL at any concentration. Either cortisol or lithium could completely block the PRL effect. Dihomo- γ-linolenic acid (DHGL) and prostaglandin E1 had effects similar to those of PRL in that they potentiated norepinephrine responses at low concentrations, inhibited at high ones, and had no effect on potassium responses. Arachidonic acid and prostaglandin E2 potentiated both norepinephriHe and potassium responses and had no inhibitory effects at high concentrations. Neither lithium nor cortisol blocked the effects of DHGL or arachidonic acid. Zinc had actions similar to those of PRL and DHGL, but which could be blocked only by lithium and not by cortisol. These results are consistent with t...
TL;DR: In this article, the sensitivity of travel costs to changes in input flows in the Wardrop equilibrium problem is studied and examples are given showing that both origin to destination and global travel costs may decrease as a result of an increase in input flow.
Abstract: The sensitivity of travel costs to changes in input flows in the Wardrop equilibrium problem is studied. Examples are given showing that both origin to destination and global travel costs may decrease as a result of an increase in input flows. Other examples show that, in the two-mode equilibrium assignment problem transit origin to destination travel costs may decrease as a result of an increase in automobile input flows.
TL;DR: Investigations of the fine structural changes observed in the hearts of cardiomyopathic hamsters at very early stages of the disease indicate that the initial changes involve the pericapillary mesenchymal cells.
Abstract: Investigations of the fine structural changes observed in the hearts of cardiomyopathic hamsters at very early stages of the disease indicate that the initial changes involve the pericapillary mesenchymal cells. Other prominent features consist of hypercontraction of cardiocytes, disruption of intercalated disks, and eventual partitioning of cardiac cells, with myofibrillar lysis. The generalized plasma membrane defect allows a net increase in calcium influx and a depression in mitochondrial respiratory control ratios. These pathologic events are in accord with previously reported increases in myocardial sympathic nerve activity.
01 Dec 1979-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, a structural model is presented for binary silicate systems of the typeMO-SiO2, whereMO is a basic oxide, in which silicate tetrahedra and oxygen “bridges” are treated as structural units.
Abstract: A structural model is presented for binary silicate systems of the typeMO-SiO2, whereMO is a basic oxide, in which silicate tetrahedra and oxygen “bridges” are treated as structural units. One single formalism applies over the entire composition range from pureMO, where the model reduces to a simple orthosilicate anion model, to pure SiO2, where the model reduces to a simple model of the breaking of oxygen “bridges” upon the addition ofMO. At intermediate compositions, chain length distributions for silicate polymer chains can be calculated from the model, even though these polymeric chains are not explicitly treated as structural units of the model. The calculated chain length distributions are in very good agreement with those calculated from the polymeric model of Masson for all systems studied. Furthermore, two dimensional (cyclic) and three dimensional (network) polymeric structures are accounted for by the present model. The model accounts well for available enthalpy, entropy, activity, and phase diagram data in the binary liquid systemsMO-SiO2 whereM = Ca, Mg, Mn, Fe, or Pb. The observed variations of ΔH with composition and from system to system are explained in terms of the energies of the various bonds and are represented by a three parameter equation. Although the model has been tested here only for liquid slags, it should be useful in understanding the structure of silicate glasses as well.
TL;DR: The deglycosylation of ovine pituitary lutropin with anhydrous HF effectively antagonized the steroidogenic activity of the native hormone in rat testicular interstitial cells.
TL;DR: Pooled correlations suggest that the degree of resemblance of BP and of weight between family members varies within and across generations, and is suitable for a genetic analysis of familial aggregation.
Abstract: Tests of homogeneity of means, variances and correlations for systolic blood pressure (BP), diastolic BP and weight among subdivisions of a smple of adoptive families are presented. The means and variances of either type of BP, but not weight, were not significantly heterogeneous among families grouped according to the number of parents and children, natural and/or adopted, in the family unit. Estimates of correlation between family members wree not heterogeneous among subdivisions for each of the three variables. Our results indicate that these data are suitable for a genetic analysis of familial aggregation. Pooled correlations suggest that the degree of resemblance of BP and of weight between family members varies within and across generations. Correlations involving the adoptees were significantly different from zero only for diastolic BP.
TL;DR: The elevated urinary free and total DA excretions in PA patients returned toward normal when their adrenal adenomas were removed, and the elevated plas...
Abstract: Plasma and urinary free and conjugated dopamine (DA) were determined, with the use of a new method of hydrolysis of conjugated catecholamines, in 29 patients with essential hypertension (EH), 4 with primary aldosteronism (PA), and 3 with phaeochromocytoma (normotensive phase), as well as in 16 control subjects. Plasma free DA is not detectable in most subjects. Mean conjugated plasma DA was found to be significantly elevated in EH, PA, and phaeochromocytoma patients [1.97 ± 0.3, 3.1 ± 0.3, and 3.3 ± 1.2 (SE) ng/ml, respectively, vs. 0.98 ± 0.1 ng/ml in control subjects]. Urinary free DA was lower in EH patients than in PA subjects. Total urinary DA was higher in PA patients than in control and EH subjects. After iv furosemide, there was less increase in the urinary excretion of sodium (P < 0.05) and free DA (P < 0.005) in EH patients than in controls. The elevated urinary free and total DA excretions in PA patients returned toward normal when their adrenal adenomas were removed. The elevated plas...
TL;DR: Inter-individual differences in oxidative O-demethylation of the drug are discussed in relation to current theories on the aetiology of schizophrenia and reported fatalities arising from abuse of theDrug.
Abstract: 1. The qualitative and quantitative aspects of the urinary elimination of orally administered 4-methoxy[14C]amphetamine have been examined in the rat and guinea-pig and in three volunteer human subjects, to determine interspecies and interindividual variations in disposition of the drug.2. Both rat and guinea-pig excreted 70-80% of the administered dose (6 mg/kg) in the urine within 24 h, mainly as metabolites.3. In the guinea-pig, the drug was metabolized by O-demethylation to give 4-hydroxyamphetamine, which was excreted free (4% dose) and conjugated (73%). No other metabolite was detected.4. The rat metabolizes the drug both by O-dealkylation and by side-chain oxidation, the products being 4-hydroxyamphetamine (5% of dose free and 60% conjugated) and 1-(4'-methoxyphenyl)propan-2-one oxime (5% dose, free and conjugated).5. In man the drug (dose 5 mg) is metabolized by O-demethylation and by side-chain oxidation. Marked intersubject variations were observed both in the array and quantitative aspects of m...
TL;DR: Chronic stress has a generally inhibitory effect on pituitary-gonadal function both in female and male rats inducing low circulating levels of LH, testosterone (T), prolactin (Prl) and, inconsistently, FSH.
TL;DR: Clinical trials of FPL 55712 as an aerosol in allergic obstructive respiratory diseases in man and animals may help to further understand the mechanism(s), and chemical mediator(s) involved in these conditions.
Abstract: Compound FPL 55712 is a highly selective antagonist of SRS-A derived from guinea-pig, rat, man and dog. It equally antagonizes SRS (slow reacting substance) released by calcium ionophore from rat basophilic leukemia cells and peritoneal mono-nuclear cells and by compound 48/80 from cat paw. In comparatively high doses FPL 55712 significantly inhibits passive cutaneous anaphylaxis in rat and anaphylactic bronchoconstriction in guinea-pig and rat and antigen-induced rhythmic mechanical activity in chicken ileum and late phase of Schultz-Dale reaction in guinea-pig trachea and human bronchus. In addition, FPL 55712 inhibits the SRS-A-induced release of rabbit aorta contracting substance (RCS) from guinea-pig lung. FPL 55712 facilitates sputum clearance in allergic canine asthma. This compound also inhibits the guinea-pig ECF-A (eosinophil chemotactic factor of anaphylaxis)-induced eosinophil chemotactic response of guinea-pig eosinophils in vitro. Compound FPL 55712 is an invaluable pharmacological tool for the identification of SRS(A) and to help define the role of SRS-A in the pathophysiology of immediate hypersensitivity (e.g. anaphylaxis and allergic asthma). Clinical trials of FPL 55712 as an aerosol in allergic obstructive respiratory diseases in man and animals may help to further understand the mechanism(s) and chemical mediator(s) involved in these conditions.
TL;DR: The present results suggest that climbing fiber-mediated vestibular information may influence the uvula and the fastigial nucleus in cats with known topography of olivocerebellar projections.