Showing papers by "Université de Montréal published in 1974"
Book•
01 Jan 1974TL;DR: Stress is the nonspecific response of the body to any demand made upon it, that is, the rate at which we live at any one moment as discussed by the authors, i.e., the wear and tear exerted upon the body.
Abstract: Stress is “the nonspecific response of the body to any demand made upon it,” that is, the rate at which we live at any one moment. All living beings are constantly under stress and anything, pleasant or unpleasant, that speeds up the intensity of life, causes a temporary increase in stress, the wear and tear exerted upon the body. A painful blow and a passionate kiss can be equally stressful.
1,737 citations
Journal Article•
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490 citations
TL;DR: In this article, extreme pure samples of clinopyroxene phenocrysts from two volcanic rocks have been analyzed for K, Rb, Cs, Sr and Ba and partition coefficients are obtained which are in the range 0.001-0.004 for K. These results are lower than those in the literature by factors of 6-100 but are in good agreement with values determined experimentally at pressures of 15-30 kb by Shimizu (Geochim.
176 citations
TL;DR: Isolated photosynthetic reaction center from the bacterium Rhodospirillum rubrum was extracted with acetone-methanol and was proposed to contain 4 moles of bacteriochlorophyll, 2 mole of bacteriopheophytin, and 1 mole of spirilloxanthin per equivalent of P870.
129 citations
TL;DR: In this paper, it was shown that only two independent O(3) scalars exist in the enveloping algebra of SU(3), namely the angular momentum L2 and the two SU (3) Casimir operators C(2) and C(3).
Abstract: We consider the ``missing label'' problem for basis vectors of SU(3) representations in a basis corresponding to the group reduction SU(3)⊃O(3)⊃O(2). We prove that only two independent O (3) scalars exist in the enveloping algebra of S U (3), in addition to the obvious ones, namely the angular momentum L2 and the two SU(3) Casimir operators C(2) and C(3). Any one of these two operators (of third and fourth order in the generators) can be added to C(2), C(3), L2, and L3 to form a complete set of commuting operators. The eigenvalues of the third and fourth order scalars X(3) and X(4) are calculated analytically or numerically for many cases of physical interest. The methods developed in this article can be used to resolve a missing label problem for any semisimple group G, when reduced to any semisimple subgroup H.
119 citations
TL;DR: In this paper, a series of analyses have been made on collections of igneous rock from the island of Kerguelen, and it is concluded that the island is not older than late Oligocene to early Miocene in outcrop, and that it migrated southwestward to its present location, away from the southeastern branch of the Mid-Indian ridge system, during the Tertiary crustal spreading episode.
Abstract: In order to contribute to resolution of the possibility that the Kerguelen-Gaussberg Ridge (in the south-central Indian Ocean) is a continental fragment remaining after separation of Gondwanaland, a series of analyses have been made on collections of igneous rock from the island of Kerguelen. Petrographic analyses and measurement of the major- and trace-element concentrations, Sr-isotopic ratios, K-Ar ages, and paleomagnetic properties of intrusive and extrusive bodies have been added to the known volcanic stratigraphy and some previously unpublished geochemical data, to arrive at a preferred origin for the island. It is concluded that Kerguelen is not older than late Oligocene to early Miocene in outcrop, and that it migrated southwest-ward to its present location, away from the southeastern branch of the Mid-Indian ridge system, during the Tertiary crustal-spreading episode. No evidence is known to suggest that the island is of continental origin. Alkali syenite bodies, some of which are rich in quartz, were intruded into shield basalt in the southwestern part of the island during late Miocene to early Pliocene time, and are late-stage differentiates, similar to those found on other oceanic islands. Even though direct sampling of unexposed parts of the ridge (during the Deep-Sea Drilling Project) may yield lower Tertiary to upper Mesozoic sedimentary and igneous rocks, it is considered unlikely that any of the samples will consist of continental material.
113 citations
TL;DR: In this article, a new small HF device alloys the production of a long electrodeless plasma column without magnetic field, and a 25 mm diameter plasma with densities 10 10 ∼ 10 11 /cm 3 and length 1.80 m can be produced with 80 W at 500 MHz.
107 citations
TL;DR: The activity of 171 neurons in the lower precentral cortex and superior temporal gyrus were recorded in monkeys making voluntary and semiautomatic rhythmical jaw movements and it was suggested that this type of neuron could control the tension developed in jaw closing muscles when their contraction is opposed by a resistance between the teeth.
Abstract: The activity of 171 neurons in the lower precentral cortex and superior temporal gyrus were recorded in monkeys making voluntary and semiautomatic rhythmical jaw movements. The discharge pattern of 75% of the precentral neurons was related to the performance of jaw movements and repetitive electrical stimulation of the region containing responsive units evoked coordinated rhythmical masticatory movements. Responsive neurons were divided according to their patterns of discharge. Fifteen neurons discharged preferentially during all types of jaw opening movements. They apparently received a proprioceptive sensory input since they fired when the jaw was opened by the experimenter. Loads which aided jaw opening increased their discharge frequency during opening movements and the maximum discharge frequency was proportional to the maximum displacement of the mandible. It was suggested that these neurons excite jaw opening motoneurons and inhibit jaw closers. Thirty-six neurons fired with a weaker phase relationship to jaw opening, 25 neurons discharged when the jaw was open and 5 neurons discharged during protrusion of the tongue. These neurons may control the many jaw, face and tongue muscles which are not principally responsible for opening or closing the jaw. Sixteen neurons were excited or inhibited throughout a series of movements, but fluctuations in their discharge frequency were not correlated to the phase of movement. Only 4 neurons discharged preferentially during closure under all conditions. Their firing frequency was not affected by loads aiding or opposing closure and did not correlate with the velocity or displacement of the jaw. Thirteen neurons discharged when the teeth were in contact or when apple was crushed between the teeth and probably received a sensory input from the periodontal pressor receptors. It was suggested that this type of neuron could control the tension developed in jaw closing muscles when their contraction is opposed by a resistance between the teeth. However, unopposed closing movements, such as those occurring during rhythmical semiautomatic tasting movements, are probably controlled at the brain stem level.
100 citations
95 citations
TL;DR: Cholesterol sulfate as well as certain analogs can project the red blood cell against hypotonic hemolysis and is produced in vitro at physiological concentrations of the sterol sulfate and both the sulfate moiety and the side chain of the molecule are necessary for biological activity.
91 citations
01 Nov 1974-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: In this article, a critical assessment is made of simple power series expansions and their limitations in representing thermodynamic properties over the entire composition range of a binary system, and the advantages of certain orthogonal series as an alternative method of representation is also discussed.
Abstract: The storage, retrieval, and manipulation of thermodynamic data with the aid of a computer requires accurate analytical representation of thermodynamic properties of solutions. In the present paper, a critical assessment is made of simple power series expansions and their limitations in representing thermodynamic properties over the entire composition range of a binary system. The advantages of certain orthogonal series as an alternative method of representation is also discussed. Particular emphasis is placed upon series representations which use Legendre polynomials due to their simplicity and the fact that their functional form is consistent with empirical observations of solution behavior. Since the coefficients of orthogonal series are independent of each other when the entire composition range of a binary system is represented, any thermodynamic property can be fitted to any desired degree of accuracy by a finite number of terms without the necessity of storing a large number of significant digits. Also, because the coefficients are uncorrelated, they are amenable to mathematical interpolation and extrapolation as well as to physical interpretation. The relationships between coefficients of series expansions of all partial and integral properties for the general case have been derived using the Gibbs-Duhem equation.
TL;DR: This is a case of malignant granular‐cell myoblastoma of the right thigh in a woman of 60 who died 129 days after she was admitted to the hospital.
Abstract: This is a case of malignant granular‐cell myoblastoma of the right thigh in a woman of 60. Pulmonary roentgenogram showed the existence of metastatic nodules. The patient died 129 days after she was admitted to the hospital. A classification of malignant granular‐cell myoblastoma was made after a review of the literature.
TL;DR: The primary diagnostics for komatiite are chemical (CaO/Al 2 O 3 > 1, MgO > 9 percent, K 2 O ) and structural (K 2 O
Abstract: The primary diagnostics for komatiite are chemical (CaO/Al 2 O 3 >1, MgO >9 percent, K 2 O
TL;DR: A correlation of therubro‐olivary projection with the distribution of the olivo‐cerebellar projection indicates that the rubro‐OLivary fibers represent one of the links in reciprocal connections between the cerebellum and red nucleus.
Abstract: The rubro-olivary projection in the macaque has been studied by making lesions in the red nucleus and mapping terminal degeneration with the method of Nauta-Laidlaw. Lesions restricted to the parvocelluar region have been obtained and confirm that the tract originates from that portion of the red nucleus. The distribution is mainly in the principal olive and in this sub-nucleus, more extensive than in the cat. Small projections to the medial accessory olive and dorsomedial cell column of the olive are also reported. A topographical arrangement of the rubro-olivary fibers was found. The projection is made of fibers of fine caliber which degenerate slowly. Optimal survival time was around 16 days. A correlation of the rubro-olivary projection with the distribution of the olivo-cerebellar projection indicates that the rubro-olivary fibers represent one of the links in reciprocal connections between the cerebellum and red nucleus.
TL;DR: Recordings were made from single neurons to identify and characterize the projection of a variety of oral-facial sites including face, oral mucosa, jaw musculature, and larynx to the frontal cortex of cats to examine the possible roles of these regions in perceptual and motor functions.
TL;DR: In this paper, a detailed study of the group of symmetries of the time-dependent free particle Schrodinger equation in one space dimension is presented, and an orbit analysis of all first-order symmets is seen to correspond in a well-defined manner to the separation of variables of this equation.
Abstract: A detailed study of the group of symmetries of the time‐dependent free particle Schrodinger equation in one space dimension is presented. An orbit analysis of all first order symmetries is seen to correspond in a well‐defined manner to the separation of variables of this equation. The study gives a unified treatment of the harmonic oscillator (both attractive and repulsive), Stark effect, and free particle Hamiltonians in the time dependent formalism. The case of a potential c/x2 is also discussed in the time dependent formalism. Use of representation theory for the symmetry groups permits simple derivation of expansions relating various solutions of the Schrodinger equation, several of which are new.
TL;DR: The ratios TMSL/LVET and PEP/ LVET being unaffected by age or HR, are suggested as practical indices of myocardial function in children, as well as three different statistical methods applied to study the separate influence of heart rate and age on these intervals.
Abstract: The systolic time intervals have been measured in 76 normal children, aged 1 month to 15 years, from simultaneous recordings of the electrocardiogram, phonocardiogram and carotid arterial pulse or apexcardiogram (left or right). Four different statistical methods were applied to study the separate influence of heart rate (HR) and age on these intervals. Left ventricular ejection time (LVET) had a highly significant correlation with HR but none with age. Age alone had a slight but significant influence on pre-ejection period (PEP) and isometric contraction time (ICT). Electromechanical systole (Q-II) varied directly with age and inversely with HR. Right and left total mechanical systole (TMS R , TMS L ) and left isometric relaxation time (IRT L ) were inversely related to HR, while right electromechanical delay varied only with age. Q to first sound interval (Q-I), interval from onset of contraction to first sound on left and right apexcardiogram (Cl L , Cl R ) and left electromechanical delay (EMD L ) were found to be constant values. PEP/LVET (0.313, sd 0.05) and TMS L /LVET (1.546, sd 0.128) were not significantly correlated with HR nor age. Regression equations and mean values are presented to permit rapid estimation of predicted normal values in children. The ratios TMS L /LVET and PEP/LVET being unaffected by age or HR, are suggested as practical indices of myocardial function in children.
TL;DR: The increased incorporation of thymidine was accompanied by a net and significant increase in total lung weight and a persistent elevation of total lung DNA and could be used as a tool to study the biochemical events leading to or accompanying stimulated DNA synthesis and cell growth in lung.
Abstract: SummaryMale Swiss-Webster mice were injected ip with 400 mg/kg of the antioxidant buty-lated hydroxytoluene (BHT). Between 2 and 5 days after BHT, there was a marked increase in the incorporation of thymidine into pulmonary DNA; 7 and 9 days after BHT, incorporation of thymidine fell towards values found in control animals. The increased incorporation of thymidine was accompanied by a net and significant increase in total lung weight and a persistent elevation of total lung DNA. Butylated hydroxytoluene did not stimulate DNA synthesis in liver, kidney, spleen, or gastrointestinal tract. Butylated hydroxytoluene could be used as a tool to study the biochemical events leading to or accompanying stimulated DNA synthesis and cell growth in lung.
TL;DR: In mice, an 18-hour pretreatment with acetone or isopropyl alcohol enhanced the capacity of threshold doses of chloro form, 1,1,2-trichloroethane, and trich chloroethylene to produce an increased hepatotoxic response as measured by increases in serum glutamic pyruvic transaminase activity.
Abstract: In mice, an 18-hour pretreatment with acetone or isopropyl alcohol enhanced the capacity of threshold doses of chloro form, 1,1,2-trichloroethane, and trichloroethylene to produce an increased hepatotoxic response as measured by increases in serum glutamic pyruvic transaminase activity. The most marked potentiation was seen with chloroform. The hepatotoxicity of 1,1,1-trichloroethane was not augmented by prior administration of isopropyl alcohol or acetone. The ability of isopropyl alcohol or acetone to potentiate the hepatotoxic response of these agents is proportional to the basic hepatotoxicity of the agent involved.
TL;DR: In this paper, the average expected cost per unit time over an infinite time span is obtained in the case where the cost structure involves a term which takes into account adjustment costs, depreciation costs or interest charges which are suffered at fixed intervals of time of equal length.
Abstract: The age replacement policy which minimizes the average expected cost per unit time over an infinite time span is obtained in the case where the cost structure involves a term which takes into account adjustment costs, depreciation costs or interest charges which are suffered at fixed intervals of time of equal length. The optimal policy is shown to be nonrandom and sufficient conditions are given for it to be finite. Stopping rules in the search of this finite solution are also given. Finally some examples illustrate the procedure of finding these optimal policies.
TL;DR: Interkinetic nuclear migration was totally inhibited in the neural cells of early chicken embryos cultured for 3 hr on media containing 5 μg/ml cytochalasin B.
TL;DR: It appears that the length of the minimum RR interval during atrial fibrillation is proportional to both the functional refractory period and the minimumRR interval obtained by atrial pacing, which may imply that the conduction velocity of a propagated impulse across the AV junction is prolonged in hearts with longer functional refraction periods.
Abstract: The relation between the minimum RR interval during atrial fibrillation and the functional refractory period of the AV junctional tissues was studied in isolated perfused dog hearts In each heart, the functional refractory period, the minimum ventricular interval obtained by regular pacing of the atria at increasing frequencies, and the minimum RR interval during atrial fibrillation were compared It appears that the length of the minimum RR interval during atrial fibrillation is proportional to both the functional refractory period and the minimum RR interval obtained by atrial pacing These values are nearly equal in preparations where the functional refractory period is short However, in cases where the functional refractory period is long, the minimum RR interval during atrial fibrillation is appreciably longer than the two other parameters It is suggested that this difference may be explained in terms of a decreased safety factor between the efficiency of the incoming atrial wavefront as a stimulus and the level of excitability of the atrioventricular junctional tissues Alternatively, these results may also imply that the conduction velocity of a propagated impulse across the AV junction is prolonged in hearts with longer functional refractory periods
01 Jan 1974
TL;DR: In this article, it was proved that the smallest 4-chromatic triangle has eleven vertices and is unique, which is the smallest known graph in the world, and the first known graph with 11 vertices.
Abstract: It is proved that the smallest 4-chromatic triangle — free graph has eleven vertices and is unique.
TL;DR: It is suggested that benign essential hypertension represents a heterogeneous entity and a continuous spectrum of clinical and biochemical changes when it is related to the level of blood pressure, which is more evident in labile hypertension.
Abstract: The clinical entity of benign essential hypertension is often subdivided into labile essential hypertension and stable essential hypertension To establish less arbitrary limits between normotension and labile and stable benign essential hypertension, 70 subjects (56 with benign essential hypertension) were classified according to (a) the usual blood pressure index for each subject and (b) the upper limit of variation of the usual blood pressure indexes of a normotensive population Catecholamines, plasma renin activity, and urinary creatinine, sodium, and potassium were measured in recumbent subjects who had received a controlled-sodium diet Our findings suggest that (1) benign essential hypertension represents a heterogeneous entity and a continuous spectrum of clinical and biochemical changes when it is related to the level of blood pressure, (2) adrenergic involvement is more evident in labile hypertension, (3) regardless of the urinary excretion of catecholamines in subjects with benign essential hypertension the urinary ratio of dopamine to norepinephrine always remains lower, and (4) a negative correlation exists between urinary sodium excretion and usual blood pressure indexes
TL;DR: In these patients, the result of aortocoronary bypass appears less predictable than in patients with classic angina, and one patient still has documented attacks of variant angina in spite of a patent vein graft.
TL;DR: The properties of the low-lying states of doubly even selenium nuclei have been investigated via multiple Coulomb excitation effected with 39.2 MeV oxygen projectiles on thin targets.
TL;DR: This paper advocates a general method based on quadratic discriminants resulting from the application of Bayes’s theorem to probability density functions for analysing the kind of data which is likely to arise in genetic counselling.
Abstract: The practice of negative eugenics by means of prospective genetic counselling requires the ability to discriminate with high reliability between the wild and mutant genotype. This discrimination usually depends on the result of some biochemical test. Some tests, such as those which actually identify a mutant protein, e.g. HbS, identify genotypes unequivocally. However, in many cases, the data obtained from the mutant genotypes and wild genotypes overlap. This is particularly true of tests which measure enzyme activity or metabolite concentration. This type of test is often used for the identification of heterozygotes as in the current programmes for the prevention of Tay-Sachs disease. In these cases, the genotype can be identified only with a certain probability which must be correctly calculated. In some cases, two discriminatory tests are available. As will be shown, use of a second test increases the power to discriminate between genotypes but makes the calculations more difficult. Since the number of instances where heterozygote identification is desirable and the number of tests available for this purpose is likely to increase in the future, we advocate a general method for analysing the kind of data which is likely to arise. The method is based on quadratic discriminants resulting from the application of Bayes’s theorem to probability density functions. Examples of previous applications of this method to biological and medical problems are given in Smith (1947) and in Karn & Penrose (1952), though, as far as we are aware, it has never been applied to problems in the field of genetic counselling. A concise exposition of the method in matrix form is given in Smith (1969). In this paper we explain and illustrate the use of the method in genetic counselling.
TL;DR: It is postulated that ozone itself is probably exerting directly both lethal and mutagenic effects on the cells via a primary effect on the permeability of the cellular membrane.
Abstract: A procedure for the quantitative determination of ozone-induced maltose and methionine mutants in Escherichia coli K12 was defined. High yields of induced mutants with over 90% survival have been obtained when washed cells, taken from logarithmic phase of growth, were aerated by a stream of ozone (0.05–1.0 ppm) in buffer at pH 5.0 for 30 to 60 min. It is postulated that ozone itself is probably exerting directly both lethal and mutagenic effects on the cells via a primary effect on the permeability of the cellular membrane.
01 Feb 1974
TL;DR: An implicit enumeration algorithm is presented for finding the cost-minimal tree of the graph, which spans the designated subset of the nodes, and some computational results are given.
Abstract: A number of examples are given where one seeks a minimal-cost tree to span a given subset of the nodes of a connected, directed, acyclic graph (we call such a graph monotonic). Some of these examples require an algorithm to transform the problem into the form of a minimization problem in a monotonic graph; this algorithm is also given. Finally, an implicit enumeration algorithm is presented for finding the cost-minimal tree of the graph, which spans the designated subset of the nodes, and some computational results are given.