Showing papers by "McMaster University published in 1968"
TL;DR: Reliable acquisition of the pigeon's key-peck response resulted from repeated unconditional (response-independent) presentations of food after the response key was illuminated momentarily.
Abstract: Reliable acquisition of the pigeon's key-peck response resulted from repeated unconditional (response-independent) presentations of food after the response key was illuminated momentarily. Comparison groups showed that acquisition was dependent upon light-food pairings, in that order.
1,537 citations
TL;DR: In this article, K-Rb covariance in 21 suites of igneous and quasi-igneous rocks has helped resolve the question of whether the ratio K:Rb remains constant or decreases steadily during igneous differentiation.
440 citations
TL;DR: The fractionation of sulphur isotopes in the reduction of sulphate and of sulphite by the bacteria Desulphovibrio desulphuricans has been studied over a wide range of lactate concentration, temperature, electron donor, pH and conditions of growth using resting cell suspensions and cell free extracts of the bacteria as mentioned in this paper.
235 citations
TL;DR: Comparable rates and magnitudes of drinking were obtained when rats were required to press a lever for water, demonstrating that hypovolemia elicits a true motivational state of thirst rather than mere reflexive drinking.
162 citations
TL;DR: Rejection episodes in human kidney transplants are associated with the formation of platelet aggregates in the kidney and can be reversed by administration of anti-inflammatory drugs such as cortisone and phenylbutazone.
115 citations
TL;DR: In this paper, a transmission electron microscopy investigation was made of the structural defects in nickel oxide films formed at 500° and 600°C on metallographically polished polycrystalline nickel.
89 citations
TL;DR: The extent of labelling of DNA by N-methyl-N′-Nitro-N-nitroso[14C]guanidine is much lower than the extent oflabelling by the methyl-labelled radiomer.
82 citations
TL;DR: In this article, the authors derived the kinetic parameters of the lamellar decomposition of eutectoids from a model which assumes local equilibrium across and diffusion along the interface between the growing nodule and the parent phase.
75 citations
TL;DR: In this article, a neutron activation procedure for the determination of Ru, Pd, Os, Ir, Pt and Au in a single irradiation in silicate rocks, meteorites and sulfide ores has been developed.
Abstract: A neutron activation procedure for the determination of Ru, Pd, Os, Ir, Pt and Au in a single irradiation in silicate rocks, meteorites and sulfide ores has been developed. An alkali fusion was used to dissolve and mix 100 to 200 mg powder samples with appropriate carriers. The individual metals were separated and brought to a state of high radiochemical purity by distillation, ion exchange and solvent extraction techniques. Precious metal activities were counted by both γ and β-methods. The procedure was evaluated by replicate analyses of the granite and diabase rock standards, G-1 and W-1 and a Cu−Ni sulfide matte which had previously been analysed by emission spectrographic and spectrophotometric methods. The results were compared with previously published data. A major discrepancy was found only for Ir in W-1.
67 citations
TL;DR: Results indicate that TP contains only B. subtilis DNA and its total molecular weight per TP would be comparable with that of the PBS 1 genome.
55 citations
TL;DR: In this paper, the self-diffusion coefficients for monoclinic zirconia exposed in an oxygen atmosphere at 300 mm were determined for near-stoichiometric monochlinic ZIRconia and the results were interpreted by an anti-Frenkel type defect model.
TL;DR: In this paper, the growth rate, ν, and lamellar spacing of the discontinuous precipitate were measured, as well as the average a phase composition for some heat treatments.
TL;DR: In vitro trypsin activity was demonstrated from six simuliid species in three genera, including sugar-fed Simulium venustum, Cnephia dacotensis, and Prosimulium decemarticulatum, with results suggesting that as the amount of sucrose added to a blood preparation decreases, the larger is the proportion of the meal going to the midgut but the size of the Meal is reduced.
TL;DR: In this article, a slip-unslip process was observed on low strain amplitude fatigue hardened copper single crystals and the dislocation structure was composed of dense dipole-monopole mats elongated on the primary slip plane.
Abstract: A remarkably reversible slip-unslip process has been observed on low strain amplitude fatigue hardened copper single crystals. Slip lines formed on an electropolished surface in one half cycle almost vanish on the subsequentreverse half-cycle, then reappear on the next forward stroke. This process has been observed at least 300 μ below the original surface shortly after saturation. The dislocation structure was composed of dense dipole-monopole mats elongated on the primary slip plane and it is suggested that the reversibility results from interactions between these mats and their surrounding elastic matrix.
TL;DR: In this article, it is shown that unless passive constraints are acting, only a bending mode of instability is possible for the title problem with slenderness ratios exceeding 6. This leads one to question the interpretation given by beatty and hook to some recent experimental work of their.
Abstract: The title problem is studied by means of the stability criterion due to hill (1957). The stationary principle associated with Hill's criterion provides precise stability bounds for the problem which are compared with the critical loads predicted by the classical Euler formula. It is found, if one uses the slenderness ratio defined in engineering practice, that the Euler formula gives excellent estimates of the critical stress for slenderness ratios exceeding 35. Furthermore, if the results are plotted in terms of the dimensions of the underformed body and the ‘ nominal stress,’ then the Euler formula gives conservative estimates of the critical stress for slenderness ratios exceeding 6. It is proved, unless passive constraints are acting, that only a ‘bending’ mode of instability is possible. This leads one to question the interpretation given by beatty and hook (1968) to some recent experimental work of theirs.
TL;DR: The abundance and distribution of palladium, iridium and gold has been determined in manganese nodules from widely varying locations and geological environments within the Atlantic, Indian and Pacific Oceans as discussed by the authors.
TL;DR: Biotite and muscovite from rutile-bearing schists near Sudbury, Ontario, both show a linear increase of Ti content with increasing grade (475 to 725°C) as mentioned in this paper.
Journal Article•
TL;DR: In this paper, the energy density of neutron star matter is determined from Brueckner-theory calculations of nuclear matter and the pure neutron gas, and the relative density of protons, determined by minimizing the total energy, is found to increase with increasing matter density.
Abstract: The energy density of neutron star matter is determined from Brueckner-theory calculations of nuclear matter and the pure neutron gas. Three-body clusters are assumed to contribute negligibly to the nuclear energy, according to the theory of Bethe. The relative density of protons, determined by minimizing the total energy, is found to increase with increasing matter density. In addition, we find that muons would appear at about half the normal nuclear density.
TL;DR: Results presented here show that the amount of azide required to inhibit succinate oxidation in tightly coupled mitochondria respiring in state 3 is also sufficient to inhibit purified ATPase.
TL;DR: In this article, a study of inert-gas diffusion, mainly involving Kr and Xe, in ion-bombarded KCl, KBr, and KI has been made using bombardment energies up to 85 keV and doses up to 50 μA min/cm2.
Abstract: A study of inert-gas diffusion, mainly involving Kr and Xe, in ion-bombarded KCl, KBr, and KI has been made using bombardment energies up to 85 keV and doses up to 50 μA min/cm2. Two types of release behavior were observed, both of which were shown to be compatible with diffusion kinetics, at least to first approximation. Low doses led to release with a fairly well-defined ΔH of 33.5, 30.5, and 28.5 kcal/mol for KCl, KBr, and KI respectively, while high doses led to release with a somewhat variable ΔH having mean values of 44, 39, and 33.5 kcal/mol for KCl, KBr, and KI respectively. It is proposed that the low-dose release involves gas motion without an implied gas—gas or gas—damage interaction, the gas perhaps occupying the small, stable vacancy clusters recently discussed by one of the authors (Hj. M.). The high-dose release seems, by contrast, to be affected by transient gas—gas or gas—damage interactions, and is probably identical with the process found in homogeneous-labelling work between about 250 °C and the “knee” temperature. A third type of release, found in homogeneous-labelling work above the “knee”; temperature, has no parallel in ion-bombardment work. It is here tentatively attributed to the motion of small, gas-filled bubbles, and its ΔH of 7 to 14 kcal/mol is proposed to be related to that for surface diffusion of the host crystal.
Eine Untersuchung von Edelgasdiffusion, hauptsachlich Kr und Xe, wurde in Ionen-bestrahltem KCl, KBr und KJ durchgefuhrt, wobei Bestrahlungsenergien bis zu 85 keV und Dosen bis zu 50 μAmin/cm2 verwendet wurden. Zwei Typen eines Entgasungsverhaltens wurden beobachtet; fur beide wird gezeigt, das sie, wenigstens in erster Naherung, mit der Diffusionskinetik vertraglich sind. Niedrige Dosen fuhrten zur Entgasung mit einem wohldefinierten ΔH von 33,5; 30,5 und 28,5 kcal/Mol fur KCl, KBr bzw. KJ, wahrend hohe Dosen zu einer Entgasung mit einem etwas variablen ΔH mit den hauptsachlichen Werten 44; 39 und 33,5 kcal/Mol fur KCl, KBr bzw. KJ fuhrten. Es wird vorgeschlagen, das die Entgasung bei niederen Dosen eine Gaswanderung ohne Gas—Gas- oder Gas—Damage-Wechselwirkung darstellt; das Gas besetzt moglicherweise die kleinen, stabilen Luckenagglomerate, die kurzlich von einem der Autoren (Hj. M.) diskutiert wurden. Die Entgasung bei hohen Dosen scheint im Gegensatz dazu durch nichtstationare Gas—Gas- oder Gas—Damage-Wechselwirkungen beeinflust zu werden und ist wahrscheinlich identisch mit dem durch homogene Markierung zwischen ungefahr 250 °C und der “knee”-Temperatur gefundenen Prozes. Ein dritter Entgasungstyp, der durch homogene Markierung oberhalb der “knee”-Temperatur gefunden wird, hat in Ionenbestrahlungsarbeiten keine Parallele. Er wird hier versuchsweise der Wanderung von kleinen, gasgefullten Blasen zugeschrieben; es wird vorgeschlagen, das sein ΔH von 7 bis 14 kcal/Mol mit dem fur die Oberflachendiffusion des Wirtskristalls verknupft ist.
TL;DR: Gel filtration and neutron activation analysis methods were combined in work aimed at the development of methods for the determination of metals firmly bound to protein in human blood serum as discussed by the authors, and the values obtained are semiquantative.
Abstract: Gel filtration and neutron activation analysis methods were combined in work aimed at the development of methods for the determination of metals firmly bound to protein in human blood serum. The values obtained are semiquantative. A purely instrumental technique afforded data on Cu, Fe, Zn, Al and Mn but values for the latter two only were determined since Cu, Fe and Zn are already well known. The concentrations for Al and Mn were found to be 300 ppb and 0.4 ppb, respectively. Despite the high resolution of Ge(Li) detectors, no other metals were found. For the determination of any others, radiochemical separations are necessary and were used to obtain data on the following elements: As 3 ppb, Ag 3 ppb, Au 0.003 ppb, Cr 1 ppb, Sb 1 ppb, Co, Cd, Mo and Sn could not be detected and upper limits were estimated to be 0.1 ppb, 2 ppb, 2 ppb, and 1 ppb, respectively.
TL;DR: In this paper, the heat and momentum transfer analogy is employed to analyze the heat transfer phenomena for turbulent flow in concentric annuli, where a modification of the velocity distribution due to Van Driest is assumed and equations in dimensionless form are developed to predict: (a) the position of maximum velocity in the annulus; (b) the friction factor-Reynolds number relationship, and (c) temperature distributions and heat transfer relations over a wide range of Reynolds number and Prandtl modulus.
Abstract: The heat and momentum transfer analogy is employed to analyze the heat transfer phenomena for turbulent flow in concentric annuli. A modification of the velocity distribution due to Van Driest is assumed and equations in dimensionless form are developed to predict: (a) the position of maximum velocity in the annulus; (b) the friction factor-Reynolds number relationship, and (c) temperature distributions and heat transfer relations over a wide range of Reynolds number and Prandtl modulus.
TL;DR: The denaturation of PBS 1DNA with alkali was studied by determining hyperchromicity and changes in sedimentation rate and the unusually low molecular weight value for single-stranded PBS 1 DNA suggests the presence of two interruptions on the average in each strand of DNA.
TL;DR: In this article, the vapor phase absorption spectrum of oxalyl chloride in the 4000-3000 A region has been examined under high resolution and the bands are sharp in the region of the system origin, which is at 27 188.9 cm−1.
TL;DR: In this article, the authors used algebraic and stereographic procedures for determining shear elements in a two-surface analysis of any crystalline material, which can be applied to any two surface analysis of a material.
TL;DR: In this article, it was shown that the slopes of etch pits are controlled by the dissolution kinetics of the crystal, and that the size of the holes depends on the type of defect attacked and the relative rates of dissolution at the defect sites.
TL;DR: A previously undescribed virus disease has been discovered in larvae of Chironomus plumosus sampled from Lake Pepin, Wisconsin, characterized by a marked hypertrophy of the fat body and by the presence of large DNA-containing inclusions in the cytoplasm of this tissue.