Showing papers by "University of Exeter published in 1971"
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01 Sep 1971TL;DR: In this article, the authors discuss lecture objectives, factors that affect the acquisition of information, and lecture techniques that apply these factors most effectively, and alternatives when lecturing is inadequate preparation for the use of lecture techniques.
Abstract: What objectives can lectures achieve? what factors affect the acquisition of information? what lecture techniques apply these factors most effectively? alternatives when lecturing is inadequate preparation for the use of lecture techniques.
1,277 citations
TL;DR: In this article, an analysis of the Knoop indentation process is presented which establishes a clear relationship between the effective resolved shear stress (t 0 9), in the bulk of the crystal beneath the indenter, and the observed hardness.
Abstract: The results of this work, and those published by other researchers who have used Knoop indentation measurements, confirm that the nature of anisotropy in hardness is essentially determined by the crystal structure and the primary slip systems which accommodate dislocation motion during indentation. Materials belonging to the same class of crystal structure and having common slip systems possess similar anisotropic properties. The varying extent of work-hardening or fracture, associated with indentations, does not appear to influence the anisotropy— although twinning on the basal planes of hexagonal closepacked metals may have a significant effect. An analysis of the indentation process is presented which establishes a clear relationship between the ‘effective resolved shear stress’ (t 0 9), in the bulk of the crystal beneath the indenter, and the observed hardness. Directions which correspond to the minimum values of t9 e , on specific crystallographic surfaces, are those of maximum hardness and conversely. The analysis is shown to be equally applicable to a wide range of crystalline solids including nonmetallic materials, of various crystal structure, and typical f.c.c., b.c.c. and c.p.h. metals. Finally, anisotropy in hardness can be used to identify active slip systems in those crystals where it is possible for dislocations to move on more than one system.
232 citations
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TL;DR: In this article, an experimental situation was designed to investigate the differential effects of eye contact and unreciprocated gaze upon GSR activity, and the results showed that the frequency and amplitude of GSR responses were greater when subjects' gazes were reciprocated, (eye contact), than when unrecipient gaze was not reciprocated.
218 citations
TL;DR: Values of mutual inductance between two circular conductors lying in parallel planes have been computed and their relevance to the design of radio-frequency coupled implant systems is mentioned.
Abstract: Values of mutual inductance between two circular conductors lying in parallel planes have been computed. The results are presented in graphical form and their relevance to the design of radio-frequency coupled implant systems is mentioned.
97 citations
TL;DR: A one-dimensional theory of steady flow through a tube with non-uniform elastic properties is developed, the importance of the speed of pressure waves on the tube is pointed out, and the characteristics and stability of subsonic and supersonic flow are examined.
Abstract: A one-dimensional theory of steady flow through a tube with non-uniform elastic properties is developed. The importance of the speed of pressure waves on the tube (the sonic speed) is pointed out, and the characteristics and stability of subsonic and supersonic flow are examined. Subsonic flow is always stable. Stable supersonic flow is sometimes possible, but latent instability may lead to a localized transition (a hydraulic jump) to subsonic flow, associated with energy dissipation through turbulence.
81 citations
TL;DR: Evidence of a consistent pattern in the course of net assimilation following moistening after various periods of desiccation is shown, partly a consequence of delayed (and probably incomplete) recovery of photosynthesis, and partly of an enhanced initial rate of respiration.
Abstract: Summary
Anomodon viticulosus (Hedw.) Hook. & Tayl. and Porella platyphylla (L.) Lindb. show evidence of a consistent pattern in the course of net assimilation following moistening after various periods of desiccation. In the early stages of desiccation (up to 22 days at 50% RH in Anomodon viticulosus; up to 60 days in Porella platyphylla), recovery is rapid and apparently complete within c. 3–4 hours. After longer periods of desiccation the net assimilation rate is initially negative, but becomes positive after lengths of time increasing progressively to several days. This is partly a consequence of delayed (and probably incomplete) recovery of photosynthesis, and partly of an enhanced initial rate of respiration. After prolonged desiccation (more than 70 days) respiration in Anomodon viticulosus builds up to very high values over a period of about 24 hours following moistening and then falls to more normal levels, but subsequent recovery is problematical.
78 citations
TL;DR: The findings do not support Eysenck's prediction that these measures are related to Extraversion alone, but measures which discriminated between personality groups were inter-correlated.
Abstract: Eysenck's (1967) hypotheses concerning Extraversion, Neuroticism, and physiological reactivity were tested in relation to habituation. A factorial design, varying Extraversion (three levels) and Neuroticism (two levels) was employed: 60 subjects, 10 per cell. Both tonic and response measures of electrodermal activity (skin conductance) were recorded.
The results showed: (1) High Neurotics were more reactive than Low Neurotics (for two measures of habituation and total number of responses); (2) Extraversion was inversely related to spontaneous activity; (3) Latency of first response was moderately related (10% level only) both to Neuroticism (inversely) and to Extra-version (directly); (4) Tonic conductance measures failed to discriminate between groups; (5) Measures which discriminated between personality groups were inter-correlated.
Since the measures taken were related to both Extraversion and Neuroticism, the findings do not support Eysenck's prediction that these measures are related to Extraversion alone.
70 citations
59 citations
53 citations
TL;DR: In this article, a simple pumping suspended sediment sampler has been built and installed successfully in a small catchment and the results provide useful data on the variations in suspended sediment and dissolved load concentration during a storm and on the factors controlling the levels of suspended sediment concentration in a stream.
48 citations
TL;DR: Major increases occurred in the capacity of damaged potato leaf and tuber tissues to hydrolyse ribonucleic acid whilst relatively minor increases were found in the activity of acid phosphomonoesterase and acid phosphodiesterase.
Abstract: Major increases occurred in the capacity of damaged potato leaf and tuber tissues to hydrolyse ribonucleic acid whilst relatively minor increases were found in the activity of acid phosphomonoesterase and acid phosphodiesterase. Partial purification of homogenates by gel filtration on Sephadex G-100 revealed that much of the increased capacity to degrade ribonucleic acid following damage was due to increased ribonuclease activity. Although appreciable differences in the elution patterns of tuber homogenates subjected to gel filtration were observed before and after the breaking of dormancy the increased ribonuclease activity following damage was a constant feature. Actinomycin D had a relatively small effect on preventing these increases in phosphate-ester hydrolase activities whilst the effect of cycloheximide was very pronounced. Isopycnic equilibrium centrifugation experiments, using deuterium oxide as a density label, provided no evidence that the increased enzyme activity following damage was due to synthesis of new enzyme.
TL;DR: Three aquatic hyphomycetes, Anguillospora curvula sp.nov.
Abstract: Three aquatic hyphomycetes, Anguillospora curvula sp.nov., Dendrospora juncicola sp.nov. and Lemonniera cornuta Ranzoni, a new British record, are illustrated and described.
TL;DR: No stable pattern of correlations emerged, thus casting doubt on the contention that the mildly neurotic introvert succeeds best at university, and there was no evidence of curvilinearity of regression as suggested by some recent studies.
Abstract: Summary. The EPI (form A) was administered to 455 students taking the human development examination at the University of Exeter over a period of five years. Correlations between academic performance and E and N were computed both for year groups as a whole and for special groups. No stable pattern of correlations emerged, thus casting doubt on the contention that the mildly neurotic introvert succeeds best at university. There was no evidence, either, of curvilinearity of regression as suggested by some recent studies.
TL;DR: The EEG of extraverts and introverts was not differentiable; however, high neurotic groups were shown to have significantly greater EEG abundance than low neuroticgroups across several frequency bands.
Abstract: Occipital EEG was monitored during habituation trials to a regularly presented auditory stimulus. The subjects were selected in accordance with a factorial design which varied extraversion–introversion and neuroticism independently. A double-blind procedure was adopted for recording, scoring and statistical analysis. The EEG of extraverts and introverts was not differentiable; however, high neurotic groups were shown to have significantly greater EEG abundance than low neurotic groups across several frequency bands. There were no readily explicable interactions between the personality variables. For all subjects, two distinct response patterns appeared: (i) EEG attenuation (trials 1–3) and (ii) EEG augmentation (trials 4–20). Recovery time from stimulation may be longer than 10 sec. Both attenuation and augmenting responses are subject to the law of initial values. There were no differences in response amplitude or in speed of habituation for the personality groups.
TL;DR: Overall vigilance performance was significantly correlated with one measure of electrodermal habituation, latency of response to the first of a series of stimuli, and total number of responses to stimuli, while none of the measures of resting physiological activity were significantly related to vigilance performance.
Abstract: The experiment was designed to determine the value of measures of physiological activity as predictors of performance in a vigilance task. Subjects, for whom resting (EEG, heart rate, and skin conductance) and response (electrodermal) measures were available, were given an auditory vigilance task. Overall vigilance performance was significantly correlated with one measure of electrodermal habituation, latency of response to the first of a series of stimuli, and total number of responses to stimuli. None of the measures of resting physiological activity were significantly related to vigilance performance. The results are discussed in terms of Mackworth's (1969) theory of vigilance.
TL;DR: In this paper, the electrical conductivity as a function of temperature down to liquid helium temperature is measured for four single crystal specimens of magnetite, Fe 3 O 4, differing in impurity content and in stoichiometry.
TL;DR: The theoretical connection between the stream characteristics and urethral elasticity is developed and used to deduce the elastic properties of the urethra at the point which controls the stream (the distal constriction).
Abstract: Measurements on a normal male of the radius and speed of the urine stream, and the relation between them, are described. The tendency of the radius to increase with increasing stream speed is evidence that the urethral walls are elastic. The theoretical connection between the stream characteristics and urethral elasticity is developed and used to deduce the elastic properties of the urethra at the point which controls the stream (the distal constriction). Direct measurements of the pressure in the resting urethra of the same subject, using catheters of different radii, give further information on the elastic properties of the urethra between the external meatus and the external sphincter. The flow and pressure measurements together show that in this subject the stream is controlled about 3 cm from the external meatus. At this point the urethra behaves like an elastic walled tube of unstretched radius (0·16±0·02) cm, subject to an external pressure of (18±3) cm H2O, and the urethral walls have an average elastic constant per unit length of order 6×103 dyn cm−2 (6 cm H2O).
TL;DR: Occipital EEG was monitored during long-term exposure to visual stimulus arrays of five levels of complexity, finding no significant trends for low alpha (7·5–8·5 Hz) or high alpha (10·5-12·5Hz).
Abstract: Occipital EEG was monitored during long-term exposure to visual stimulus arrays of five levels of complexity. Integrated EEG output was recorded for nine separate frequency bands. The stimuli were two, four, eight, 16 or 32 randomly located white squares on a black background. Mid-alpha activity (8·5–10·5 Hz) decreased linearly with log2n, where n = number of squares in the array (P < 0·01). Beta activity (12·5–16·5 Hz) showed a quadratic trend (P < 0·02). Theta activity (5·5–7·5 Hz) increased linearly with ascending complexity (P < 0·05). There were no significant trends for low alpha (7·5–8·5 Hz) or high alpha (10·5–12·5 Hz). Brightness-control slides showed no parallel effects.
TL;DR: The role of innovation in economic and social change has proliferated in recent years, particularly within the social sciences, and with a bent towards cross-disciplinarity as mentioned in this paper.
Abstract: Innovation is not a new phenomenon. Arguably, it is as old as mankind itself. There seems to be something inherently ‘‘human’’ about the tendency to think about new and better ways of doing things and to try them out in practice. Without it, the world inwhichwe livewould look very, very diVerent. Try for amoment to think of a world without airplanes, automobiles, telecommunications, and refrigerators, just to mention a few of the more important innovations from the not-too-distant past. Or—from an even longer perspective—where would we be without such fundamental innovations as agriculture, the wheel, the alphabet, or printing? In spite of its obvious importance, innovation has not always received the scholarly attention it deserves. For instance, students of long-run economic change used to focus on factors such as capital accumulation or the working of markets, rather than on innovation. This is now changing. Research on the role of innovation in economic and social change has proliferated in recent years, particularly within the social sciences, andwith a bent towards cross-disciplinarity. In fact, as illustrated in Figure 1.1, in recent years the number of social-science publications focusing on innovation has increased much faster than the total number of such publications.
TL;DR: In this paper, the limiting mixing conditions of complete segregation and maximum mixedness for a continuously operated, homogeneous reactor have been extended to the case where the vessel is fed by two reactant streams having unequal residence time distributions.
TL;DR: The theory of flow through elastic-walled tubes, developed previously (Griffiths, 1971a) is applied to steady flow through collapsible tubes, in particular to one model system (Conrad, 1969).
Abstract: The theory of flow through elastic-walled tubes, developed previously (Griffiths, 1971a) is applied to steady flow through collapsible tubes, in particular to one model system (Conrad, 1969). The experimental observations are well accounted for. The collapse to small cross-section which sometimes occurs in this and similar systems is a sign that the mean flow velocity locally exceeds the sonic velocity (the velocity of pressure waves on the tube). The consequences for the study of venous blood flow are briefly examined.
TL;DR: Rats feeding ad libitum under normal laboratory conditions and the positions of mature Hymenolepis diminuta and terminal proglottids showed two movements, change in body length and movement along the intestine, thus they appear to be dependent upon the passage of nutrientsAlong the intestine.
TL;DR: Occipital EEG was monitored during a slow presentation rate vigilance task and reaction time to “wanted signals” does not correlate with measures of pre-signal EEG.
Abstract: Occipital EEG was monitored during a slow presentation rate vigilance task. EEG samples were taken for each of 400 task events. The EEG is correlated with increases and decreases in “expectancy” built into the task. Post-trial subjective estimates of alertness parallel the EEG changes. Reaction time to “wanted signals” does not correlate with measures of pre-signal EEG.
TL;DR: In this article, a numerical method is used to solve the differential equations and boundary conditions for the two-dimensional models and the surface variations of the various components are compared for the different dimensions and overburden depths.
Abstract: Summary
Field distributions and surface effects of two-dimensional conductivity inhomogeneities are investigated. Inhomogeneities of different thicknesses at the Earth's surface and also inhomogeneities of fixed sizes but at various depths are considered. A numerical method is used to solve the differential equations and boundary conditions for the two-dimensional models. The surface variations of the various components are compared for the different dimensions and overburden depths. Important differences are found in the behaviour of the apparent resistivities calculated for H and E polarizations of the applied field.
TL;DR: The background, aims and misconceptions surrounding the National Health Service are looked at and its record in achieving one of its many confessed objectives—that of territorial justice is appraised.
TL;DR: In this article, an examination of the complex taxon Botrytis cinerea was undertaken using 107 characters expressed quantitatively for thirty-three isolates, and two biometric analytical methods, principal component analysis and cluster analysis, were applied to the data.
Abstract: An examination of the complex taxon Botrytis cinerea was undertaken using 107 characters expressed quantitatively for thirty-three isolates. Two biometric analytical methods, principal component analysis and cluster analysis, were applied to the data. Both methods gave similar results but loss of information occurred in cluster analysis because the results could be represented in two dimensions only. The results suggested that the thirty-three isolates could be grouped into different races but differences were not great enough to warrant placing any isolate in a new taxon.
TL;DR: Treatment of an elongating internode with the hormones resulted in an increase in inhibition of bud growth by IAA in the presence of GA3, and all possible combinations of IAA and GA3 within the concentration range 101 to 105 μg/g lanolin were antagonistic.
Abstract: Indole-3-acetic acid (IAA) applied to the fully elongated second internode of decapitated Phaseolus multiflorus plants always inhibited axillary bud elongation at concentrations down to 100 μg/g lanolin, whereas gibberellic acid (GA3) enhanced bud elongation at concentrations down to 1000 μg/g lanolin. Lower concentrations than these of either IAA or GA3 were without significant effect. All possible combinations of IAA and GA3 within the concentration range 101 to 105 μg/g lanolin were antagonistic; IAA tending to inhibit, and GA3 promote, axillary bud elongation growth. Treatment of an elongating internode with the hormones resulted in an increase in inhibition of bud growth by IAA in the presence of GA3.
TL;DR: The time after acquisition at which actinomycin becomes effective in impairing memory, the extent of diffusion of the drug vehicle through brain tissue and the effect of the quantities of theDrug used on brain RNA synthesis are determined.
Abstract: CURRENT selectional models of learning and memory1–3 suggest that messenger RNA (mRNA) is implicated in biochemical processes in the brain which mediate long term memory. The role assigned to mRNA in these models is that of a carrier of information to the ribosome complex from environmentally stimulated derepressed regions of the DNA molecule. The specific protein molecule or peptide thus produced is supposed to signpost or colour-code neurones in such a way that conduction of subsequent impulses, similar to that which first specified the existence of the molecule, is facilitated. The loss of RNA from such a system should prevent the production of the specific protein molecule and impair the formation of a permanent memory trace, but experiments which have attempted to prevent the synthesis of mRNA by means of actinomycin during avoidance learning have given ambiguous results4–7. We have therefore set out to determine, in an appetitive learning situation, the time after acquisition at which actinomycin becomes effective in impairing memory, the extent of diffusion of the drug vehicle through brain tissue and the effect of the quantities of the drug used on brain RNA synthesis.
TL;DR: An analysis of data from a study on learning to type shows very clearly that simultaneous processing of stimulus input and response output is possible.
Abstract: Two viewpoints of attention are compared: one assumes restrictions in a central processor and the other restrictions on simultaneous activity in networks of processes. The distinction between centr...