Showing papers by "McMaster University published in 1971"
TL;DR: In this article, a set of definitions related to the concept of accessibility are discussed and various operational forms of these definitions are illustrated with reference to the Hamilton, Ontario, urban area.
Abstract: Ingram D. R. (1971) The concept of accessibility: A search for an operational form, Reg. Studies 5, 101–107. The importance of the concept of accessibility in the literature of urban studies requires that a method be found of describing quantitatively the accessibility at a point. The paper is concerned with, firstly, a set of definitions related to the concept of accessibility. A distinction is made between the relative accessibility between two points and the integral, or total, accessibility at a point. Secondly, various operational forms of these definitions are illustrated with reference to the Hamilton, Ontario, urban area. The derivation of the various measures that are developed is discussed. A measure based on the normal, or Gaussian curve is recommended as the most suitable form for determining the integral accessibility at a given point.
611 citations
TL;DR: In this article, the problem of adjusting monthly or quarterly time series to make them conform with independent annual totals or averages without introducing artificial discontinuities is considered, and a general approach and some specific procedures involving constrained minimization of a quadratic form in the differences between revised and unrevised series are proposed.
Abstract: This article considers the problem of adjusting monthly or quarterly time series to make them accord with independent annual totals or averages without introducing artificial discontinuities. A general approach and some specific procedures involving constrained minimization of a quadratic form in the differences between revised and unrevised series are proposed. Some computational advantages are noted. Attention is given to the relationships between the adjustment problem and earlier work by other authors on the creation of monthly or quarterly series when only annual figures are available. An example is provided to illustrate the application of the proposed adjustment procedures.
446 citations
TL;DR: Hooded rats trained to use olfactory cues to locate scented food pellets buried in an open field were unable to do so following bathing of the o aroma mucosa with a 5% zinc sulphate solution, leading to peripherally-induced anosmia.
250 citations
TL;DR: In this paper, it is hypothesized that if the tributary area of a gateway city is large enough and productive enough to support the rise of large central places, then the gateway will be shorn of much of its previous hinterland and will itself come to function as a central place.
Abstract: Gateway cities develop between areas of differing intensities or types of production; they are located towards one end of their tributary areas; and they are heavily committed to transportation and wholesaling. It is hypothesized that if the tributary area of a gateway city is large enough and productive enough to support the rise of large central places, then the gateway will be shorn of much of its previous hinterland and will itself come to function as a central place. The pattern of growth of Winnipeg fits the sequence set out in the hypothesis. Briefer case studies of Cincinnati, St. Louis, Minneapolis-St. Paul, and Cluj also support the hypothesis. The rise of gateways is dependent upon the presence of threshold values for distance, and levels of productivity. The gateway concept may help explain the existence of twin cities, but is in opposition to the basic spatial postulate of the von Thunen model.
203 citations
178 citations
TL;DR: Electroencephalographic activity of the hippocampus was recorded from unanesthetized rabbits during periods of movement, non-movement, sleep and tonic immobility, and Hippocampal rhythmic slow activity (RSA) was present in all these states, even in quiet sleep.
146 citations
TL;DR: In both the conditioned suppression situation with rats and the eyelid conditioning situation with rabbits, preconditioning experience with the conditioning stimuli retardation was most pronounced in subjects which had preexposure to the CS and the US in a backward-paired manner.
128 citations
TL;DR: Basal bodies are constructed during transformation and, in cells transforming synchronously at 25°C, they are first seen about 10 min before flagella are seen, and are discussed in the light of hypotheses about the continuity of centrioles.
Abstract: Amebae of Naegleria gruberi transform into flagellates whose basal bodies have the typical centriole-like structure The amebae appear to lack any homologous structure, even during mitosis Basal bodies are constructed during transformation and, in cells transforming synchronously at 25°C, they are first seen about 10 min before flagella are seen No structural precursor for these basal bodies has been found These observations are discussed in the light of hypotheses about the continuity of centrioles
127 citations
TL;DR: In this paper, the authors compared three constitutive relations due to Blatz, Blatz and Ko, and the present work are compared, and concluded that these relations predict different behaviour when a material is compressible.
110 citations
TL;DR: By using [8-(14)C]-N(6)-(Delta(2)-isopentenyl)adenosine as a substrate, the presence of enzyme activity in a crude extract of tobacco tissue that converts this cytokinin into adenosine is detected.
Abstract: By using [8-(14)C]-N(6)-(Delta(2)-isopentenyl)adenosine as a substrate, we detected the presence of enzyme activity in a crude extract of tobacco tissue that converts this cytokinin into adenosine. The extract also contains strong hydrolase activity that converts adenosine to adenine.
108 citations
TL;DR: In this article, a finite element technique is used to determine the natural frequencies and the mode shapes of a cantilever plate mounted on the periphery of a rotating disc, where the plate is assumed to make any arbitrary angle with the plane of rotation of the disc.
Abstract: A finite element technique is used to determine the natural frequencies and the mode shapes of a cantilever plate mounted on the periphery of a rotating disc. The plane of the plate is assumed to make any arbitrary angle with the plane of rotation of the disc. The distributed centrifugal force is resolved into two components—one acting in the plane of the plate and the other normal to the plate. The stresses produced in the middle surface of the plate due to the in-plane forces are first determined. The increase in the bending stiffness of the plate elements due to these in-plane stresses is obtained in a manner similar to that used in the stability analysis of plates. The component of the distributed centrifugal force normal to the plate surface is added to the inertia force.
From the results of computations carried out for various values of the aspect ratio, the speed of rotation, the disc radius and the setting angle, empirical formulae are derived giving the effect of these parameters on the natural frequencies. These empirical formulae are observed to be in agreement with the corresponding known formulae for rotating cantilever beams, when the aspect ratio is high.
TL;DR: An examination of the kinetics of synthesis and release of virus-specific proteins from VSV-infected cells showed that the rate of virus protein synthesis was maximal about 4 hr post infection, a constant proportion of the newly synthesized protein being released from the cell at all times.
TL;DR: In this paper, a local effective interaction that reproduces the G-matrix elements from an infinite nuclear matter calculation using the Reid potential is constructed, which is suitable for finite nucleus Hartree-Fock studies in the local density approximation, where sensitivity to the above listed properties can be studied systematically.
TL;DR: In this article, the simple optical theory of aggregated metal systems, due to Maxwell-Garnett, is analyzed and the complex dielectric constant of the system, and that of the constituent metal aggregates, are represented as transformations.
Abstract: In this part, the simplest optical theory of aggregated metal systems, due to Maxwell-Garnett, is analyzed. The complex dielectric constant of the system, and that of the constituent metal aggregates, are represented as transformations. The functions show single and double poles in certain regions of physical interest, indicating resonance behavior. These features are explored for free-electron metals, and an optical "conduction resonance" for the aggregated system is discovered. The resonance frequency and the magnitude of the optical conductivity are calculated, along with the plasma frequency and the magnitude of the bulk electron loss function. A relation between conduction and plasma resonances is established and it is found to be independent of the free-electron parameters of the metal. This, and other results, indicate that the conduction resonance is a macroscopic effect, being due to a collective polarization interaction between the constituent metal aggregates, and it may be looked upon as a kind of transverse plasma resonance. In the second part, the present results will be applied to real metals.
TL;DR: It is concluded that failure in DNA repair in fibroblasts from xeroderma pigmentosum is probably not causal to aging in vitro or in vivo.
Abstract: SummaryDeficient DNA repair in fibroblasts from xeroderma pigmentosum is expressed as markedly reduced survival after low doses of uv. However, the life-span in vitro of XP cells is not reduced below normal age-matched controls. Senescence of normal cells in vitro, measured by decreased plating efficiency, appears before any measurable decline in either the capacity for DNA repair or survival following uv. In no cases was spontaneous transformation to permanent cell lines observed. It is concluded that failure in DNA repair is probably not causal to aging in vitro or in vivo.
01 Mar 1971
TL;DR: In this article, a novel experimental technique for the measurement of surface tension of molten metals has been developed based on the Rayleigh equation which relates frequency and surface tension for an oscillating drop.
Abstract: A novel experimental technique for the measurement of surface tension of molten metals has been developed. It is based on the Rayleigh equation which relates frequency and surface tension for an oscillating drop. A systematic study has shown this equation to be valid for a liquid metal droplet levitated electromagnetically in an inert flowing gas with no prior calibration required. It is, therefore, an absolute method. The frequencies of oscillation of droplets of pure iron and nickel in a 6 pct H2-He gas mixture were measured by high speed cinematography. Surface tensions were obtained for temperatures of 1550° to 1780°C for iron and 1475° to 1650°C for nickel.
TL;DR: In this paper, the power of the F-test was calculated under non-normal situations and compared with the normal-theory values of the power in analysis-of-variance.
Abstract: The values of the power of the F-test employed in analysis-of-variance are calculated under non-normal situations and compared with the normal-theory values of the power Non-normality seems to have little effect on the power of the F-test
TL;DR: In this paper, a model for duration discrimination which specifies that discriminability depends only on the difference in duration between the two brief flashes, and is independent of their durations, is presented and applied to the data.
Abstract: The data from four experiments indicate that when Os discriminate between light flashes of different durations, for durations for which Bloch’s law has been shown to hold, their discriminations are frequently made on the temporal information available in the flashes rather than on their apparent brightness. A model for duration discrimination which specifies that discriminability depends only on the difference in duration between the two brief flashes, and is independent of their durations, is presented and applied to the data.
TL;DR: Wild rat pups maintained on ad lib food in a large enclosure with feeding sites not visible from nesting areas ingest their first samples of solid food at the same time and in the same place as adults of their colony.
Abstract: Wild rat pups maintained on ad lib food in a large enclosure with feeding sites not visible from nesting areas ingest their first samples of solid food at the same time and in the same place as adults of their colony. Blind pups maintained under the same conditions do not take initial meals of solid food in the presence of adults.
TL;DR: In this paper, the reactions of C 5 Me 5 M(CO) 2 [(Ia, M = Rh; (Ib), M = Ir] with methyl iodide are described.
TL;DR: In this article, the (pentamethylcyclopentadienyl) rhodium and -iridium chlorides (C 5 Me 5 -MCl 2 ) 2 reacted with silver acetate to give the acetates, which in turn gave the trifluoroacetates, C 5 ME 5 M(OCOCF 3 ) 2 ·H 2 O, with CF 3 COOH.
TL;DR: The increased aerobic metabolism observed with both ADP and polylysine may be related to changes that occur when platelets change shape and adhere to each other and it may not be a specific reaction to ADP.
TL;DR: In this article, the effect of off-low pulsations on a 4 in dia air-fluidized bed of glass beads has been investigated in the frequency range 1 to 10 Hz.
TL;DR: The low activity of trypsin and chymotrypsin between the larval-pupal and pupal-adult ecdyses presumably relates to the lack of feeding during this period of Aedes aegypti.
TL;DR: The sinusoid (antidune) bed forms and their associated internal cross-strata were preserved by the rapid fall-out of sediment from suspension normal to the bed as discussed by the authors.
Abstract: Single-set cross-stratification, considered to have been produced by the upstream migration of antidunes, is present in the basal division of certain thick turbidite beds.
The basal divisions of these turbidites consist of very coarse to medium sand with a smooth or fluted base and sinusoid top. Internal laminae are inclined upstream at a shallow angle (less than 15°), opposing the local paleocurrent direction shown by flutes and ripple-drift cross-lamination.
The sinusoid (antidune) bed forms and their associated internal cross-strata were preserved by the rapid fall-out of sediment from suspension normal to the bed.
A paleohydraulic analysis suggests that during the final stages of antidune growth and migration, the currents moved at approx. 1 m/sec over very low slopes (much less than 1°).
TL;DR: In this article, the optimal location of any number of facilities in relation to any number (m) of destinations on the Euclidean plane is investigated, where the destinations may be either single points, lines or rectangular areas.
Abstract: This article is concerned with the optimal location of any number (n) of facilities in relation to any number (m) of destinations on the Euclidean plane. The criterion to be satisfied is the minimization of total weighted distances where the distances are rectangular. The destinations may be either single points, lines or rectangular areas. A gradient reduction solution procedure is described which has the property that the direction of descent is determined by the geometrical properties of the problem.
TL;DR: The 2790 A absorption system of ethynylbenzene (phenylacetylene) and three deuterated isomers has been analyzed in this article, showing that only small changes in geometry occur on electronic excitation.
TL;DR: In this article, numerical methods for the solution of Tung's axial dispersion equation have been developed and comprehensively evaluated and can be applied where the instrumental spreading function is unsymmetrical and nonuniform.
Abstract: Numerical methods for the solution of Tung's axial dispersion equation have been developed and comprehensively evaluated. These methods are general and can be applied where the instrumental spreading function is unsymmetrical and nonuniform. Computation times required are comparable to those of the method of Chang and Huang being about 10 sec per case on the CDC6400 computer. Memory requirements are minimal and this should permit their use with minicomputers for data acquisition and processing.
TL;DR: The purpose of the present article is not so much to describe techniques in detail, but more to elucidate the underlying physicochemical principles of radioactive fibrinogen.
Abstract: Clinical interest in labelled fibrinogen outgrew the existing narrow channels of supply some time ago, and to meet the continuously increasing demand, possibilities of establishing a central source for this material are now being seriously considered in the United Kingdom. If, as it is widely hoped, these plans succeed, many new users will find themselves confronted with a variety of questions as how to make the best use of radioactive fibrinogen. The present article was conceived first of all with those in mind who lack personal experience with this protein. Its purpose is not so much to describe techniques in detail, but more to elucidate the underlying physicochemical principles.
TL;DR: In this article, a d.c. tunnel current saturation under negative bias is observed for N -type MOS devices when average oxide thicknesses of d 0 A and non-degenerate (10Ω cm) semiconductors are employed.
Abstract: A d.c. tunnel current saturation under negative bias is observed for N -type MOS devices when average oxide thicknesses of d 0 A and non-degenerate (10Ω cm) semiconductors are employed. A model is proposed that allows the voltage distribution across devices in such a non-equilibrium situation to be calculated. Theoretical tunnel current expressions are derived and a comparison with experimental results made. The dependence of the existence of this saturation on semiconductor doping concentration, oxide thickness, and minority carrier injection is investigated. Consideration of band tunnel currents, and the effects of surface state charge, oxide charge, and work function differences on these currents, is shown to be sufficient to explain much of the observed current-voltage characteristic.