Showing papers by "University of Oxford published in 1978"
TL;DR: In this article, the authors consider the possibility that psychological treatments for phobias operate by modifying action-outcome expectations, without altering efficacy expectations, and they find no evidence to support Bandura's contention that psychological procedures, whatever their form, serve as means of creating and strengthening expectations of personal efficacy.
3,220 citations
TL;DR: The experiments established the usefulness of the bybrid myeloma technique in preparing monospecific antibodies against human cell surface antigens and highlights the possibilities not only of obtaining reagents for somatic cell genetics, but also of obtaining mouse antibodies detecting human antigenic polymorphisms.
1,892 citations
TL;DR: In this article, the authors present a self-contained account of the ideas of R. Penrose connecting four-dimensional Riemannian geometry with three-dimensional complex analysis, and apply this to the self-dual Yang-Mills equations in Euclidean 4-space and compute the number of moduli for any compact gauge group.
Abstract: We present a self-contained account of the ideas of R. Penrose connecting four-dimensional Riemannian geometry with three-dimensional complex analysis. In particular we apply this to the self-dual Yang-Mills equations in Euclidean 4-space and compute the number of moduli for any compact gauge group. Results previously announced are treated with full detail and extended in a number of directions.
1,574 citations
TL;DR: In this article, a complete construction for all self-dual euclidean Yang-Mills fields is given, involving only linear algebra, and the construction is shown to be complete.
1,467 citations
TL;DR: In a longitudinal study of one mother-infant dyad, using video-recordings of their free play in a period between 0, 8 and 1; 6, it was found that the child's lexical labels were more adult-like substitutes for earlier communicative forms that he had utilized in the dialogue as discussed by the authors.
Abstract: The achievement of labelling was investigated in a longitudinal study of one mother–infant dyad, using video-recordings of their free play in a period between 0; 8 and 1; 6. Analysis of joint picture-book reading revealed that this activity had very early on the structure of a dialogue. The child's lexical labels might be regarded as more adult-like substitutes for earlier communicative forms that he had utilized in the dialogue. These were smiling, reaching, pointing and babbling vocalizations, all of which were consistently interpreted by the mother as expressing the child's intention of requesting a label or providing one. Participating in a ritualized dialogue, rather than imitation, was found to be the major mechanism through which labelling was achieved.
1,040 citations
TL;DR: The results indicate that steroid treatment is not beneficial and can be detrimental in acute neuropathy of undetermined aetiology in Guillain-Barré syndrome.
954 citations
TL;DR: Results are reported which suggest that difficulties in groupings of words which are different but which have sounds in common may be a significant source of difficulty in learning to read.
Abstract: LEARNING to read and write involves auditory perception, for the child must learn how different kinds of sounds are written. It might seem, however, that although auditory perception is essential to reading, it would not be a significant source of difficulty, for, apart from a few exceptional cases, most children who have difficulties with reading can hear perfectly well, and can discriminate and understand the words which they signally fail to read1. But discriminating words is not the only aspect of audition involved in reading. The child must also be able to group together words which are different but which have sounds in common. If he is to learn the rules of reading and writing he must understand that ‘hat’, ‘cat’ and ‘mat’, though different, nevertheless have a sound in common. We report here results which suggest that difficulties in this kind of grouping may be a significant source of difficulty in learning to read.
766 citations
TL;DR: When great tits forage in an unknown environment containing two feeding places of different profitability, they first sample the two places and then exploit the more profitable one.
Abstract: When great tits forage in an unknown environment containing two feeding places of different profitability, they first sample the two places and then exploit the more profitable one. The balance between sampling and exploitation shown by the birds is close to an optimal solution for maximising the number of food-items obtained during a feeding period.
606 citations
TL;DR: This paper shows experimentally that male toads, Bufo bufo, settle contests for the possession of females by means of vocalisations that give a reliable signal of body size and hence of fighting ability.
Abstract: ANIMALS often settle disputes by means of conventional displays. It has been suggested that this enables the contestants to assess each other's strength without resorting to a serious fight1. If this is true then we would expect natural selection to favour displays which give reliable information about fighting potential; assessment signals that are easily mimicked by weak individuals will not be evolutionary stable2,3. Often the outcome of a contest will depend simply on who is the larger, and many displays seem to involve assessment of body size1,4. In this paper we show experimentally that male toads, Bufo bufo, settle contests for the possession of females by means of vocalisations that give a reliable signal of body size and hence of fighting ability.
577 citations
TL;DR: Experiments showed that escalated contests only occurred when both contestants ‘thought’ they were the resident, and support the theoretical predictions of Maynard Smith & Parker (1976) that contests are costly and territories abundant.
571 citations
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01 Jan 1978TL;DR: In this article, the effects of Lag in biological models are discussed and a model with a single Discrete Lag is proposed, and conditions under which spreading the Lag does not affect local stability are discussed.
Abstract: 1. Introduction.- a. Discrete and Distributed Lag.- b. Origin of Lags in Biological Models.- c. Lag as an Alternative to Age Structure.- d. Lag as an Alternative to Spatial Structure.- e. The Effects of Lag.- f. Lags and Stochastic Models.- 2. Stability Analysis.- a. The Linear Chain Trick.- b. Instantaneous Models.- c. Models with a Single Discrete Lag.- d. Models with a Single Distributed Lag.- e. An Inequality for Distributed Lag.- f. The Monod Chemostat Model.- g. May's Model of Obligate Mutualism.- 3. Periodic Solutions.- a. Periodic Solutions of the Linear Chain Equations.- b. The Method of Hastings, Tyson and Webster.- c. Hopf Bifurcation.- d. Numerical Integration.- 4. Logistic Growth of a Single Species.- a. Discrete Lag.- b. Distributed Lag in a Model of a Self-poisoning Population.- c. Linear Chain Calculations.- d. Hopf and H.T.W. Methods.- e. Constant Harvesting of a Population in the Presence of Lag.- f. Poincare-Lindstedt Method for Discrete Lag.- g. An Epidemic Model Related to the Logistic Equation.- 5. Biochemical Oscillator Model.- a. The Goodwin Model.- b. Necessary Condition for Instability.- c. Expanding the Set of Equations.- d. A Single Goodwin Equation with Lag.- e. Discrete Lag in the Goodwin Equation.- 6. Models of Haemopoiesis.- a. Wheldon's Model of Chronic Granulocytic Leukemia.- b. Two-lag Models of Cyclical Neutropenia.- c. Time Lag with Attrition a Model of Cyclical Pancytopenia.- 7. Predation Models of the Volterra Type.- 8. Difference Equation Models.- a. Stability Analysis.- b. Conditions under which Spreading the Lag does not affect Local Stability.- c. Chaos in Discrete Dynamical Systems.- d. Extended Diapause in a Single Species Population Model.- e. Analogous Treatment of a Functional Differential Equation.- Supplementary Bibliography.- References.
TL;DR: Some principles which might guide the design of knee prostheses are deduced and it is shown that current designs transgress some of these principles.
Abstract: The mechanisms controlling and limiting movement and serving to transmit load between the femur and the tibia are discussed. Having accounted for the transmission of all components of force and couple across the joint and noted the load-bearing role of the menisci, some principles which might guide the design of knee prostheses are deduced. It is shown that current designs transgress some of these principles. An experimental prosthesis is then described, which incorporates analogues of the natural menisci. The possible practical application of this novel principle has been studied in cadaveric human joints and in living patients.
TL;DR: Muscular fatigue has been studied using 31P NMR to measure the levels and rates of utilisation of several key metabolites and the free-energy change for ATP hydrolysis.
Abstract: Muscular fatigue has been studied using 31PNMR to measure the levels and rates of utilisation of several key metabolites and the free-energy change for ATP hydrolysis. Force development is closely correlated with metabolite levels and is proportional to the rate at which ATP is hydrolysed.
TL;DR: The paper describes habitat preferences, spacing, range sizes, group composition and territorial behaviour of the European badger in a study area in southern England.
Abstract: The paper describes habitat preferences, spacing, range sizes, group composition and territorial behaviour of the European badger in a study area in southern England. Animals were followed at night with the aid of radio-location and night-vision equipment, and colour-marked food was used to establish range-size.
TL;DR: It is shown that great tit song plays a part in territory maintenance by experiments in which ‘occupied’ territories with loudspeakers after removing resident pairs, and the possibility that repertoires enhance the effectiveness of song as a territorial display was tested.
Abstract: BIRD song is generally considered to have one or both of two main functions : attracting a mate and proclaiming a territory. The great tit (Parus major) is a typical songbird in that song is primarily a male vocalisation and it is produced before and during the breeding season (that is, from January to May in southern England). We have shown that great tit song plays a part in territory maintenance by experiments in which we ‘occupied’ territories with loudspeakers after removing resident pairs1,2. New pairs seeking an empty space in which to settle moved into control areas more rapidly than into song-occupied territories. We report here on three experiments designed to study the effect of a varied song repertoire in territory maintenance. Each male great tit, in common with many other songbird species, has a repertoire of song variants some of which are usually shared between birds in a locality. In the great tit, repertoire size commonly varies between two and eight song types. In some species, for example the canary, elaborate repertoires seem to be favoured by sexual selection3,4, but we have found no evidence for this in the great tit (Table 1), in which pairing takes place before the spring peak of song. We therefore tested the possibility that repertoires enhance the effectiveness of song as a territorial display.
TL;DR: The flow of official aid from the members of the OECD Development Assistance Committee rose rapidly until 1961 as mentioned in this paper, and then the total increased rather slowly, with a trend rate of 3.1 per cent a year.
Abstract: The flow of official aid from the members of the OECD Development Assistance Committee rose rapidly until 1961. Thenceforward, however, the total increased rather slowly. In 1961 net official aid, i.e. gross disbursements minus amortisation, was $5,210 million; in 1968 it was $6,471 million.1 This represents an increase over the period of less than a quarter and a trend rate of growth of about 3.1 per cent a year. In the period 1962–8 the annual average rate of increase was 2.5 per cent, i.e. exactly equal to the rate of increase of the population in the underdeveloped countries. In other words, the amount of foreign aid available per caput has not increased since 1962.
TL;DR: Analysis of appearance and disappearance games revealed a restricted format with a limited number of semantic elements, and a highly constrained set of semantic relations; a clear repetitive structure, which allowed both for anticipation of the order of events and variation of the individual elements.
Abstract: The nature of early games and how they might assist the infant in language acquisition were explored in a longitudinal study of two mother–infant dyads, using video-recordings of their free play. Analysis of appearance and disappearance games, in particular, revealed: (1) a restricted format, with a limited number of semantic elements, and a highly constrained set of semantic relations; (2) a clear repetitive structure, which allowed both for anticipation of the order of events and variation of the individual elements; (3) positions for appropriate vocalizations which could in turn be used to mark variations; and (4) the development of reversible role relationships between mother and child.
TL;DR: In this article, four possible mechanisms for short-term item recognition are distinguished: pure list search, direct access activation (or trace strength) discrimination, mixtures (of I and II), and response association.
TL;DR: This work has compared the rates of invasion and growth of P. falciparum in normal red cells and in those of individuals with the sickling disorders, in both aerobic conditions and conditions of reduced oxygen tension, and suggests a possible mechanism for the protection of sickle-cell heterozygotes against P. Falconerum malaria.
Abstract: RELATIVE protection against Plasmodium falciparum malaria afforded to heterozygous carriers of the sickle-cell gene is now the accepted mechanism for the high frequency of the gene in areas where malaria is (or was) common1–3. However, the cellular mechanisms whereby Hb S protects the red cell against the malarial parasite are still not fully understood. We have compared the rates of invasion and growth of P. falciparum in normal red cells and in those of individuals with the sickling disorders, in both aerobic conditions and conditions of reduced oxygen tension. As a result of these studies, we suggest a possible mechanism for the protection of sickle-cell heterozygotes against P. falciparum malaria.
TL;DR: Given a finite number of quantum states with {\em a priori} probabilities, the positive operator-valued measure that maximizes the Shannon mutual information is investigated and the group covariant case is examined in detail.
Abstract: Given a finite number of quantum states with {\em a priori} probabilities, the positive operator-valued measure that maximizes the Shannon mutual information is investigated The group covariant case is examined in detail
TL;DR: In this paper, the authors derived a relation for total earth heat loss as a function of the rate of plate creation and the amount of heat transported to the base of plates, which suggests that a significant proportion of the heat loss in the Archaean must have taken place by the processes of plate creating and subduction.
TL;DR: In this paper, the problem of percolation through an n × n sponge is introduced and the FKG inequality of Fortuin, Kasteleyn, and Ginibre is proved.
Abstract: Publisher Summary This chapter focuses on bond percolation on the square lattice and briefly describes percolation model; this model is a special but perhaps the most interesting case of the general theory of percolation. It introduces the FKG inequality of Fortuin, Kasteleyn, and Ginibre; it proves a remarkable inequality showing that nondecreasing functions on a finite distributive lattice are positively correlated by all positive measures, which have a certain convexity property. The problem of percolation through an n × n sponge is introduced. The chapter also examines two of the possible critical probabilities pT and pH and uses the theory developed for the sponge problem to prove the result pT + pH = 1. By the percolation model on G, one mean the assignment of open or closed to each edge of G with probabilities p and q = 1 - p respectively, the assignments to be independent for each edge.
TL;DR: Delivery at term of a low birth weight infant was significantly associated with maternal prepregnant weight, maternal height, maternal smoking, primiparity, maternal employment, low social class, a previous infant of low birthWeight, threatened abortion and severe toxaemia.
TL;DR: In this paper, three simple rules are proposed that enable the prediction of the most favorable position of nucleophilic attack on 18 electron organotransition metal cations containing unsaturated hydrocarbon ligands.
TL;DR: A hypothesis is presented which suggests that the physiography of the area determined worm-patch dispersal, and thereby the range size of the badgers, whilst the number of badgers in each range, i.e. the group size, is determined by the ‘quality’ of the food patches.
Abstract: 1.
Food and foraging behaviour of the European badger (Meles meles L.) are described for a study area in south-central England, with the aim of understanding the biological function of badgers' spatial organisation. Animals were followed with the aid of radio-location and observed through infra-red night glasses.
2.
The diet consisted largely of one species of earthworm, Lumbricus terrestris.
3.
Worm abundance was measured by formalin-sampling of different vegetation types, and prey appeared to be super-abundant.
4.
Prey availability was restricted; badgers caught worms on the surface at night, where worms could be found in small and temporally highly unstable patches. Factors influencing the existence of these ‘worm-patches’ are discussed.
5.
A hypothesis is presented which suggests that the physiography of the area determined worm-patch dispersal, and thereby the range size of the badgers, whilst the number of badgers in each range, i.e. the group size, is determined by the ‘quality’ of the food patches.
6.
It is suggested that one of the selective advantages of a larger group size is the joint territorial defense.
TL;DR: The first detailed evidence of inbreeding depression in a natural population is presented and support for the hypothesis that one function of dispersal between birth and breeding sites is to reduce an individual's chance of in breeding is supported.
Abstract: IN populations which normally outbreed, matings between close relatives can result in a decrease in the viability and fertility of their offspring. Such inbreeding depression has been shown in a number of laboratory studies of insects1, birds2 and mammals3. We present here the first detailed evidence of inbreeding depression in a natural population and support for the hypothesis4 that one function of dispersal between birth and breeding sites is to reduce an individual's chance of inbreeding.
TL;DR: A general theory is presented for selective or “tailored” excitation by an arbitrary modulation of the radiofrequency transmitter signal, and it confirms earlier conclusions that the frequency-domain excitation spectrum corresponds to the Fourier transform of the transmitter modulation pattern.