Showing papers by "University of Oxford published in 1983"
TL;DR: This paper found that children who are backward in reading are strikingly insensitive to rhyme and alliteration and are at a disadvantage when categorizing words on the basis of common sounds even in comparison with younger children who read no better than they do.
Abstract: Children who are backward in reading are strikingly insensitive to rhyme and alliteration1. They are at a disadvantage when categorizing words on the basis of common sounds even in comparison with younger children who read no better than they do. Categorizing words in this way involves attending to their constituent sounds, and so does learning to use the alphabet in reading and spelling. Thus the experiences which a child has with rhyme before he goes to school might have a considerable effect on his success later on in learning to read and to write. We now report the results of a large scale project which support this hypothesis.
2,960 citations
TL;DR: In this article, Li has been inserted chemically and electrochemically into Mn3O4 and Li[Mn2]O4 at room temperature from X-ray diffraction.
1,555 citations
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1,146 citations
TL;DR: In this article, it was shown that carbon-hydrogen bonds may act as ligands to transition metal centers forming covalent CH⇀M systems in which the H group donates two electrons to the metal.
1,098 citations
TL;DR: In this paper, the effects of the proton irradiation sequence by means of a train of spin rotation operators, the overall effect at the end of the cycle being calculated by explicit matrix multiplication, the offset dependence of this proton response determined the residual splitting of the carbon-13 resonance and hence the effectiveness of the decoupling.
1,026 citations
TL;DR: This work has prepared and tested an anti-somatostatin–anti-peroxidase bi-specific antibody and found that this way of producing hybrid molecules is superior to the production of hybrid antibodies by chemical reconstitution methods because the drastic treatment required for chain separation in the latter is likely to lead to some protein denaturation and loss of antibody activity.
Abstract: A normal antibody-producing cell only expresses one antibody, resulting in the well-known phenomenon of allelic exclusion. When two myeloma cells are fused, the derived hybrids are capable of co-dominantly expressing the antibody genes of both parents. Although the respective variable (V) and constant (C) region genes remain expressed in the same cis configuration, heavy and light chains of both parents are scrambled, and hybrid molecules are formed. The same is true when a myeloma and an antibody-producing cell are fused to produce a hybrid myeloma (hybridoma). Fusion therefore allows the production of hybrid immunoglobulin molecules containing two different combining sites. Hybrid molecules of this type retain antigen-binding activity and specificity. Bispecific monoclonal antibodies secreted by hybridomas may have a variety of uses in biology and in medicine. Here we have focused on their application in histochemistry. As an example, we have prepared and tested an anti-somatostatin-anti-peroxidase bispecific antibody. This way of producing hybrid molecules is superior to the production of hybrid antibodies by chemical reconstitution methods because the drastic treatment required for chain separation in the latter is likely to lead to some protein denaturation and loss of antibody activity. Intracellularly synthesized and assembled hybrids do not suffer from this disadvantage. In addition, the recombination of heavy and light chains from different antibody molecules is likely to lead to considerable waste.
863 citations
TL;DR: Organic inhibitors of calcium influx prevent outward as well as inward current through cardiac calcium channels but do not slow current activation, and organic drugs show varying degrees of use-dependent block.
Abstract: Organic inhibitors of calcium influx prevent outward as well as inward current through cardiac calcium channels but do not slow current activation. Although block is antagonized by raising external calcium or barium concentrations, the competitive effect of permeant cations does not occur at the same cation binding site at which inorganic blockers act. Organic drugs show varying degrees of use-dependent block, due in part to blockade of open channels. Nitrendipine blockade of calcium currents requires doses >100-fold higher than expected from radioligand binding to isolated membranes.
848 citations
TL;DR: New pulse sequences for solvent suppression in Fourier transform NMR are derived and evaluated, and the most satisfactory sequences consist of equally spaced hard pulses with lengths in the ratio of binomial coefficients and phases alternating between 0 and 180°.
805 citations
TL;DR: Neurons in the orbitofrontal cortex of the alert rhesus monkey possess highly coded information about which stimuli are present, as well as information about the consequences of the animal's own responses, which may constitute a neuronal mechanism for determining whether particular visual stimuli continue to be associated with reinforcement, aswell as providing for the modification of theAnimal's behavioural responses to such stimuli when those responses are no longer appropriate.
Abstract: Single unit recording of neurons in the orbitofrontal cortex of the alert rhesus monkey was used to investigate responses to sensory stimulation. 32.4% of the neurons had visual responses that had typical latencies of 100–200 ms, and 9.4% responded to gustatory inputs. Most neurons were selective, in that they responded consistently to some stimuli such as foods or aversive objects, but not to others. In a number of cases the neurons responded selectively to particular foods or aversive stimuli. However, this high selectivity could not be explained by simple sensory features of the stimulus, since the responses of some neurons could be readily reversed if the meaning of the stimulus (i.e. whether it was food or aversive) was changed, even though its physical appearance remained identical. Further, some bimodal neurons received convergent visual and gustatory inputs, with matching selectivity for the same stimulus in both modalities, again suggesting that an explanation in terms of simple sensory features is inadequate.
799 citations
771 citations
TL;DR: In this article, a new scheme for low-power broadband heteronuclear decoupling is described, based on the use of a composite radiofrequency pulse sequence 90°( + X ) 180°(− X ) 270°(+ X ), incorporated into a repeated cycle or supercycle.
TL;DR: A 'septo-hippocampal syndrome,' consisting of the effects common to both lesions, is delineated, and divergences between the effects of the two lesions are noted.
TL;DR: In this article, the cosmological implications of N = 1 supergravity with the Polonyi potential were studied, and it was shown that for typical values of the gravitino mass (102-103 GeV) the universe goes through a late period of reheating (i.e., from a temperature of about 10 -7 MeV to 10 -2 MeV).
TL;DR: An alternate derivation from a model assuming continuous velocity control of hand position is shown to fit the motion time data equally well, and an internal “secondary positional reference” must be postulated to explain results obtained when S is deprived of visual feedback.
Abstract: Fitt's empirical result is stated and its information theoretic interpretation briefly discussed. An alternate derivation from a model assuming continous velocity control of hand position is shown to fit the motion time data equally well. Detailed studies of hand motion trajectories in Fitts' reciprocal tapping task have confirmed the exponential target approach predicted by this model but also revealed systematic fluctuations that it cannot explain. A further alternate model is therefore presented, based on intermittent feedback with target approach by a sequence of discrete positional corrective motion “impulses”. The second model also predicts motion times in accord with Fitts' Law. Detailed studies of target aimed translational hand and rotary wrist motions have shown that the intermittent corrective impulses are of approximately Gaussian integral form, with minimum s.d. on the order of 30 msec. for wrist rotation, and recurrence rate about 10/s. Mechanical and physiological interactions capable of ex...
TL;DR: In this article, it is suggested that an important dimension of cognitive vulnerability to depression may be the nature of the cognitions that become accessible in depressed mood, which may form the basis of a vicious cycle which will perpetuate and intensify depression.
TL;DR: In this paper, an extensive study of the surface and bulk properties of both single-crystal and polycrystalline Fe2O3 is reported surface pretreatment is found to have a major effect on the photoelectrochemical properties Even in properly treated samples, however, the photocurrent onset is delayed due to the small value of the faradaic rate constant for the oxidation of water.
Abstract: Iron(III) oxide has been extensively studied as a possible n-type semiconductor for use in solar photoelectrolysis cells However, its properties have remained curiously elusive; even such fundamental properties as bandgap and flat-band potential are still controversial, and this uncertainty has hindered any rational evaluation of the use of the material in solar cells In this paper, an extensive study of the surface and bulk properties of both single-crystal and polycrystalline Fe2O3 is reported Surface pretreatment is found to have a major effect on the photoelectrochemical properties Even in properly treated samples, however, the photocurrent onset is found to be delayed due to the small value of the faradaic rate constant for the oxidation of water, and a semi-quantitative treatment of this case is provided Improper surface treatment is shown to lead to a substantial conversion of the surface of Fe2O3 to Fe3O4; this introduces a large fraction of recombination sites at the surface that not only delay dc photocurrent onset to very anodic potentials but also reduce the observed efficiency to remarkably low values
TL;DR: The concept of the flexibility of manufacturing systems is topical and important for three reasons as discussed by the authors : the instability and unpredictability of the environment, in which manufacturing companies operate, has forced many companies to reorganise their production, if only to reduce the overall scale of their operations.
Abstract: The concept of the flexibility of manufacturing systems is topical and important for three reasons. First, the instability and unpredictability of the environment, in which manufacturing companies operate, has forced many companies to reorganise their production, if only to reduce the overall scale of their operations. Second, developments such as flexible manufacturing systems and robotics, mean that flexibility is being explicitly promoted as a desirable attribute of production equipment. Third, the relatively recent interest in the nature of production management objectives has widened the scope of production aims beyond cost and productivity issues, to include the flexibility of production systems.
TL;DR: The number of ganglion cells in the retina of the postnatal rat has been examined and the number of axons in the optic nerve and the cells which can be retrogradely labelled with horseradish peroxidase from injections into the brain was estimated in this paper.
Abstract: The number of ganglion cells in the retina of the postnatal rat has been examined. We estimated both the number of axons in the optic nerve and the number of cells which can be retrogradely labelled with horseradish peroxidase from injections into the brain. In the retina of the newborn rat there are at least twice as many ganglion cells as in the adult rat. By retrograde labelling of the ganglion cells and following transection of their axons 24-48 hrs later we can find no evidence that ganglion cells withdraw their axon without degeneration of the patent cell body. We have found that the excess ganglion cells are lost over the first ten postnatal days and during this period we observe pyknotic nuclei in the ganglion cell layer. From our estimates of the total number of neurones in the ganglion cell layer and the number of ganglion cells found at different ages we conclude that the migration of amacrine cells into the ganglion cell layer occurs in the first five postnatal days.
TL;DR: Neurons were studied in the striate cortex of the cat following intracellular recording and iontophoresis of horseradish peroxidase to identify large basket cells with high horizontal extent of axonal arborization, which may receive input on its soma, apical and basal dendrites and spines from the same large basket cell.
TL;DR: In this article, the concept of an "ethological need" has assumed a prominent place in recent discussions of animal welfare, although the term itself is surrounded by confusion, and it is argued that some of this confusion might be overcome by applying consumer demand theory to some of the problems in animal welfare.
TL;DR: In this article, a review of the tensile impact testing of composite materials is given and a new method, using a modified version of the standard tensile split Hopkinson's pressure bar (SHPB), is described.
Abstract: A brief review is given of techniques which have been employed in attempts to determine the mechanical properties of composite materials under tensile impact loading. The difficulties encountered in the design of a satisfactory tensile impact testing machine for composite materials are discussed and a new method, using a modified version of the standard tensile split Hopkinson's pressure bar (SHPB), is described. Dynamic stress-strain curves for unidirectionally-reinforced carbon/epoxy composite, in which failure occurs in less than 30 μsec at a mean strain rate of about 400 sec−1, are presented and their validity is established. An extension of the technique to allow the testing of wovenroving reinforced glass/epoxy composites is described and dynamic stress-strain curves obtained for which the times to failure approach 100 μsec and the average strain rate is of the order of 1000 sec−. Comparative stress-strain curves at low and intermediate rates of strain are obtained and the effect of strain rate, over about 7 orders of magnitude, on the tensile modulus, and strength, fracture strain and energy absorbed in fracturing is determined. The limitations of the technique are discussed.
TL;DR: In this article, all solutions of the Einstein equations admitting super-covariantly constant spinors in the sense of Gibbons and Hull are found, and two classes corresponding to stationary charged dust and plane waves with dust respectively.
TL;DR: Evidence that neurons in this system may produce additional peptides, which were originally characterized as the circulating hormones released from the neurohypophysis, may have an additional important role in influencing the activity of central neurons through direct projections to these neurons.
Abstract: Publisher Summary Vasopressin and oxytocin projections may be involved in the regulation of autonomic activity, and the paraventricular nuclei (PVN) sends vasopressin and oxytocin projections to various autonomic centers in the brainstem and spinal cord. This chapter discusses the immunohistochemical studies on the distribution, morphology, and projections of neurons producing classical neurohypophysial peptides and presents evidence that neurons in this system may produce additional peptides. Vasopressin and oxytocin are associated with a family of low molecular weight proteins, the neurophysins, also present in the extracts of the neurohypophysis. Vasopressin and oxytocin are present in fibres throughout the mammalian central nervous system. In target areas, fibres surround and contact neurons and in some cases these contacts have been identified as synaptic. In a number of these areas, vasopressin and oxytocin have been shown to alter the electrical or biochemical activity of neurons, and may be involved in various centrally regulated functions. There is evidence that both vasopressin and oxytocin can alter the electrical activity of neurons in various parts of the central nervous system, where fibres containing these peptides are present. Thus these peptides, which were originally characterized as the circulating hormones released from the neurohypophysis, may have an additional important role in influencing the activity of central neurons through direct projections to these neurons.
TL;DR: In this article, the authors consider the range of evidence for the secondary uses and products of animals: traction, transport, wool and milk, and suggest that early farming populations used livestock mainly for meat, and that other applications were explored as agriculturalists adapted to new conditions, especially in the semi-arid zone.
Abstract: This paper considers the range of evidence for the secondary uses and products of animals: traction, transport, wool and milk. It suggests that early farming populations used livestock mainly for meat, and that other applications were explored as agriculturalists adapted to new conditions, especially in the semi‐arid zone. Innovations in different parts of the Near East were exchanged and disseminated as part of the process leading to urbanisation. Their dispersal affected both the steppe belt, which saw a marked increase in population, and also temperate Europe, where agriculture was revolutionised by more extensive methods of farming and landscape clearance.
TL;DR: In this paper, it was shown that any self-dual SU (2) monopole may be constructed either by Ward's twistor method, or Nahm's use of the ADHM construction.
Abstract: We show that any self-dual SU (2) monopole may be constructed either by Ward's twistor method, or Nahm's use of the ADHM construction. The common factor in both approaches is an algebraic curve whose Jacobian is used to linearize the non-linear ordinary differential equations which arise in Nahm's method. We derive the non-singularity condition for the monopole in terms of this curve and apply the result to prove the regularity of axially symmetric solutions.
TL;DR: A human α2-globin gene is identified which contains a single point mutation in this hexanucleotide (AATAAA → AATAAG), and readthrough transcripts extending beyond the normal poly(A) addition site are detected in mRNA obtained from HeLa cells transfected with cloned DNA from the mutant α2 gene, suggesting that the single nucleotide change in the AATAAA sequence is the cause of its abnormal expression.
Abstract: Most eukaryotic messenger RNAs have the sequence AAUAAA 11–30 nucleotides from the 3′-terminal poly(A) tract1,2. Since this is the only significant sequence homology in the 3′ non-coding region it has been suggested that it may be a recognition site for enzymes involved in polyadenylation and/or termination of polymerase II transcription2–4. This idea is strengthened by observations on the effect of deletion mutations in or around the AATAAA sequence on polyadenylation of late simian virus 40 (SV40) mRNA; removal of this sequence prevents poly(A) addition3. Naturally occurring variants ofthis hexanucleotide are rare5–11 and hitherto their functional significance has not been assessed. We have now identified a human α2-globin gene which contains a single point mutation in this hexanucleotide (AATAAA → AATAAG). The paired α1 gene on the same chromosome is completely inactivated by a frame-shift mutation. This unique combination has enabled the expression of the mutant α2 gene to be studied in vivo where it has been found that the accumulated level of α2-specific mRNA in erythroid cells is reduced. Furthermore, readthrough transcripts extending beyond the normal poly(A) addition site are detected in mRNA obtained from HeLa cells transfected with cloned DNA from the mutant α2 gene, suggesting that the single nucleotide change in the AATAAA sequence is the cause of its abnormal expression.
TL;DR: A high-efficiency expression vector is constructed to direct the synthesis of heterologous polypeptides in yeast to produce derivatives of the calf chymosin cDNA gene, which can be readily activated to produce an enzyme which has milk-clotting activity.
TL;DR: The persistence of shrunken cholinergic neurons in the basal nucleus in the diseased brain is similar to that seen in an experimental study of retrograde cellular degeneration in the nucleus following damage of the cortex.
TL;DR: It is concluded that HLFA is likely to be involved in the nonspecific adherence or lytic functions of killer cells rather than specific antigen recognition.
Abstract: Human lymphocyte function antigen (HLFA) is a cell surface protein defined by two monoclonal antibodies MHM23 and MHM24. It is present on both B and T lymphocytes but in greater amounts on the latter. Both antibodies precipitated antigen, from radiolabeled HSB-2 cells, which ran as two chains on sodium dodecyl sulfate polyacrylamide gel electrophoresis at 180 and 94 kDa. Neither antibody inhibited binding of the other, indicating that distinct epitopes were recognized. Both antibodies were shown to inhibit HLA-restricted lysis of influenza virus-infected and Epstein-Barr virus-transformed target cells by cytotoxic T lymphocytes. Blocking occurred at the level of the effector cells and in the presence of subsaturating concentrations of antibody. Both reagents also inhibited lysis of K562 cells, mediated by natural killer cells. These blocking effects differ from the inhibitory effects of monoclonal anti-HLA ABC and anti-suppressor cytotoxic T cell antibodies which inhibit only HLA-restricted lysis when present in saturating amounts. It is concluded therefore that HLFA is likely to be involved in the nonspecific adherence or lytic functions of killer cells rather than specific antigen recognition.