Showing papers by "Keele University published in 1983"

The communication of musical metre in piano performance.

Abstract: Six pianists of varying levels of experience were required to give repeated performances of a note sequence presented for sight-performance under two conditions. The two conditions differed only in the location of metrical stresses signified by the notation. In condition (b) the bar-lines and beams were shifted one note to the right in comparison to condition (a). Details of note duration and intensity were recorded by computer. This allowed the discovery of significant differences in expressive treatment between the two conditions. There were significant agreements between subjects concerning the position, nature and direction of expressive variation. The more experienced players, however, made greater use of expressive variation than did the less experienced players. In a second experiment listeners were asked to identify the metre of each performance from the first experiment. They achieved greatest success at this with the most experienced player, least success with the least experienced player. A det...

Structures and textures in Triassic braided stream conglomerates (‘Bunter’ Pebble Beds) in the Sherwood Sandstone Group, North Staffordshire, England

Abstract: In the northern parts of the Needwood and Stafford/Eccleshall Basins, England, the Pebble Beds of the Sherwood Sandstone Group contain thick successions of texturally mature, fluvial pebble/cobble conglomerates which are organized into either horizontal or cross-stratified sets. The horizontally lying sets, generally coarser grained and more poorly sorted than the cross-bedded sets, are usually disorganized and either matrix- or clast-supported, although thin lenses of well-sorted, occasionally openwork units, interpreted as falling stage phenomena, are often present. The cross-stratified conglomerates have foresets exhibiting remarkable textural organization, with a coarse, bimodal (sometimes matrix-supported) part grading upwards or being abruptly overlain by a finer, well-sorted (occasionally openwork) part and finally capped by sandstone. These rhythmic textural changes are attributed partly to an avalanche process at high stage and partly to falling stage conditions. The most common types of vertical association are thick successions of horizontally bedded conglomerates (up to 20 m) and sequences of an upwards coarsening nature (2-12 m) in which cross-stratified sets are overlain by flat-lying sets. The environment of deposition of the gravels is interpreted as one in which water depths at high stage were greater than depths in most modern braided stream plains (proglacial or alluvial fan) but shallower than depths associated with the Pleistocene catastrophic floods from which texturally mature, giant gravel bars have been recorded. Recent braided streams with relatively confined channels and considerable bar/channel relief are better analogues. In particular, medial or mid-channel bars with a two-tier structure (subaqueous and partly emergent portions) may explain the upward-coarsening sequences in which horizontally lying conglomerates overlie cross-stratified conglomerates. The thicker sequences of horizontally stratified conglomerates represent proximal, longitudinal bar deposits. Sheets of pebbly sandstone and argillaceous sandstone lying between the conglomerates, and commonly occurring towards the top of the succession, largely represent deposition from sandwaves and dunes. Finer, interbedded, argillaceous sandstones, siltstones and mudstones are interpreted as overbank and waning-flood deposits. Basin-forming tectonism of increasing intensity probably caused the initial coarsening upwards of the lower part of the succession, whilst more stable tectonic conditions and decreasing relief on the margins of the basins and in the areas of provenance in the Midlands and the Hercynides, account for the upwards-fining of the upper part of the succession.

Polymers containing enzymatically degradable bonds, 7. Design of oligopeptide side-chains in poly[N-(2-hydroxypropyl)methacrylamide] copolymers to promote efficient degradation by lysosomal enzymes†

Abstract: N-(2-Hydroxypropyl)methacrylamide copolymers are considered to be a potential drug delivery system. To fulfil this role the drug-polymer linkage must be susceptible to intralysosomal hydrolysis. Taking p-nitroanilide as a drug analogue, copolymers were synthesized bearing oligopeptidyl-p-nitroanilide side-chains designed to match known specificities of the lysosomal enzymes cathepsin L or cathepsin D. Degradation of side-chains by rat liver lysosomal enzymes (measured by monitoring terminal p-nitroaniline release) occurred only in the presence of reduced glutathione (5 mmol/l) and was effectively inhibited by leupeptin, indicating the involvement of thiol-proteinases in every case. Depending on side-chain composition, between 20 and more than 50% of the terminal p-nitroaniline residues were liberated during a 5 h incubation. It has also been shown that 1) a polymer molecule may contain side-chains of a single type that are nevertheless differentially susceptible to lysosomal hydrolysis; 2) two of the side-chains studied liberate only a p-nitroaniline residue, whereas the others also release amino-acyl-p-nitroanilides; 3) the cleavage of all side-chains displays a broad pH optimum pH 5 to pH 7; 4) the Michaelis-Menten constant Km for side-chain cleavage varied between 26,1 and 143,2 mg/ml, depending on the amino acid sequence of the side-chain.

Evidence that protein ingested by the rat visceral yolk sac yields amino acids for synthesis of embryonic protein.

Abstract: [ 3 H]Leucine-labelled haemoglobin was prepared from rat reticulocytes incubated in the presence of [ 3 H]leucine. Conceptuses from 9·5-day pregnant rats were incubated in vitro for 48 h, with [ 3 H]leucinelabelled haemoglobin present for the final 12, 8, 4, 2 or 0·5 hours. Radioactivity accumulated in visceral yolk sac and in embryonic tissue. When exposure to labelled haemoglobin was for only a short period before harvesting, all the radioactivity found in the embryo and most of that found in the visceral yolk sac was trichloroacetic acid-soluble (i.e. associated with free amino acid rather than with protein). After longer exposures the proportion of radioactivity that was acid-soluble decreased to minimum values of about 20 %. SDS-polyacrylamide gel electrophoresis of the protein-associated radioactivity in visceral yolk sac and embryo was performed. After exposure to labelled haemoglobin for 1 h only prior to harvesting, the yolk sac contained a single peak of radioactivity coincident in mobility with haemoglobin. The embryo contained no protein-associated radioactivity. After exposure to labelled haemoglobin for 12 h, many protein bands in both yolk sac and embryo were radiolabelled. Thus a single radiolabelled protein pinocytically captured by the visceral yolk sac can give rise to the presence of many labelled proteins in embryo and visceral yolk sac. These results indicate that the source protein underwent proteolytic digestion and that the amino acids generated were re-utilized for protein synthesis in both embryonic and visceral yolk-sac cells.

Interstellar ice grains in the Taurus molecular clouds

Abstract: We report here observations made in November 1981 using the United Kingdom Infrared Telescope (UKIRT) at Mauna Kea of the 3 µm ice absorption feature in the spectra of several obscured stars in the Taurus interstellar clouds. The feature correlated in strength with extinction at visual wavelengths (Av), and is present in stars with Av as low as 4–6 mag, a remarkable result when compared with other regions of the Galaxy. Ice may be widespread in the Taurus clouds, vindicating ideas on grain composition and growth first reported nearly 50 yr ago1.

Ethical Particularism and Morally Relevant Properties

Abstract: Defense du particularisme ethique, i.e. de la theorie suivant laquelle nos decisions ethiques sont prises cas par cas et non en vertu de principes moraux. L'A. s'appuie sur une discussion de W. D. Ross, The Right and the Good (Oxford, 1930).

Problem‐solving ability and cognitive structure‐an exploratory investigation

Abstract: (1983). Problem‐solving ability and cognitive structure‐an exploratory investigation. European Journal of Science Education: Vol. 5, No. 2, pp. 171-184.

The level of phospholipase A2 activity is raised in the uninvolved epidermis of psoriasis

Abstract: SUMMARY The activity of phospholipase A2 was measured in uninvolved psoriatic epidermis and normal epidermis. The mean phospholipase A2 activity in uninvolved psoriatic epidermis, expressed as nmol fatty acid released per mg protein per h, was raised compared with normal epidermis (7.88±s.e. 1·20 vs 2.18±s.e. 0·38; P<0·01). This observation is, we believe, the first demonstration of an abnormality in the uninvolved untreated psoriatic epidermis which could account for the pathology of the disease.

Inhibition of proteolysis in rat yolk sac as a cause of teratogenesis. Effects of leupeptin in vitro and in vivo

Abstract: Conceptuses from 9.5-day pregnant rats were cultured for 48 h in heat-inactivated homologous serum to which leupeptin, a specific inhibitor of the lysosomal cysteine-proteinases, was added for the final or the penultimate 6 h. The presence of leupeptin (25 micrograms/ml or above) increased the protein content of yolk sacs at harvesting to approximately twice the control value. The protein content of the embryo at harvesting was lower than that of controls. When 125I-labelled polyvinylpyrrolidone was added to the culture serum for the final 6 h of culture, radioactivity was found in the yolk sac at harvesting, but not in the embryo. The presence of leupeptin did not affect the rate of uptake of the radiolabelled macromolecule by the yolk sac, nor facilitate its entry into the embryo. When formaldehyde-denatured 125I-labelled bovine serum albumin was added to the culture medium for the final 6 h of culture, little radioactivity was found in the yolk sac at harvesting, and barely any was found in the embryo. Trichloroacetic acid-soluble radioactivity was found in the culture serum. The presence of leupeptin sharply increased the levels of radioactivity in the yolk sac (but not the embryo) and sharply decreased the acid-soluble radioactivity of the culture medium. When rat serum whose proteins were labelled with [3H]leucine was used as culture medium, radioactivity was found in both yolk sac and embryo at harvesting. The presence of leupeptin increased the amount found in the yolk sac and decreased that found in the embryo. These results are interpreted as follows. Leupeptin enters the lysosomes of the yolk sac, inhibiting their cysteine proteinases. The digestion of proteins pinocytosed by the yolk sac is consequently inhibited, resulting in the accumulation of protein by the yolk sac and a decreased flow of amino acids to the embryo. Leupeptin (50 mg/kg), injected into pregnant rats at either 8.5 days or 9.5 days of gestation, induced congenital malformation in the offspring. It is proposed that leupeptin exerts its teratogenic action by inhibiting proteolysis in the lysosomes of the yolk sac, and so depriving the developing embryo of its supply of amino acids at a critical stage of development.

Conformational transitions in oriented fibres of the synthetic polynucleotide poly[d(AT)].poly[d(AT)] double helix.

Abstract: The synthetic polynucleotide poly[d(AT)]·poly[d(AT)] is of interest in studies of the relationship between nucleic acid structure and function. In particular, A+T-rich regions in DNA double helices have been invoked as centres for controlling the transcription of genetic information. Here we describe conditions for observing by X-ray fibre diffraction the A, B, C and D conformations of Na-poly[d(AT)]·poly[d(AT)], and for inducing transitions between these conformations. The D form emerges as a particularly stable conformation; once assumed, it persists over a wide range of variation in the relative humidity of the fibre environment. Further, while transitions between the B and D conformations are readily reversible, transitions between A and D are much more complex.

The effects of headings in text on recall, search and retrieval

Abstract: Summary. This paper summarises the results from nine experiments on headings. The experiments centre on three main variables (i) the purpose of the task (recall, search or retrieval from familiar and unfamiliar text); (ii) the position of the headings (marginal or embedded); and (iii) the nature of the headings (statements or questions). The results showed that headings aided recall, search and retrieval from the text used in these experiments, but that the position of the headings (marginal or embedded) had no effect. The kind of headings (questions or statements) had no differential effect with readers of different ability but low-ability participants appeared to do better with headings as questions in the recall tasks.

The Meaning and Use of ‘Political Stability’*

Abstract: Few extended analyses of the concept of political stability have been published, much of the literature concentrating on an analysis of its causes. This article discusses the main approaches to stability and examines two recent conceptualizations by Ake and by Sanders. It is argued that both are unsatisfactory, and an alternative definition is developed, starting from first principles. The problems of identity and change are examined, and what counts as the survival of a political object is specified. A stable political object is defined as one that possesses the capacity to prevent its own forced non-survival. It is argued that stability cannot be quantified and that there are thus no degrees of stability.

Some pharmacological properties of neuromuscular transmission in the oviduct of the locust, Locusta migratoria

Abstract: The effects of various pharmacological agents on neurally evoked contractions of the visceral muscles of the oviduct of Locusta migratoria have been examined. The pentapeptide, proctolin, at low concentrations (10−11 M−10−10 M), induced an increase in the amplitude of neurally evoked contractions and basal tonus, and induced the appearance and increased the frequency of myogenic contractions. Glutamate, at 10−4 M, produced a small transient contraction which in some preparations was accompanied by a reduction in amplitude of neurally evoked contractions. Octopamine, at 10−6 M, reduced the amplitude of neurally evoked contractions and also resulted in a relaxation of the muscles. The octopaminergic effects were inhibited by the α-aminergic antagonist phentolamine. Neurally evoked contractions were unaffected by dopamine, 5-HT or the acetylcholine receptor antagonists atropine and hexamethonium. Acetylcholine increased the amplitude of neurally evoked contractions, but only at the high concentration of 10−3 M. The possible role of proctolin and glutamate as excitatory neuro-transmitters and the inhibitory action of octopamine is discussed.

Physiological characteristics of photosynthesis in porphyridium cruentum: evidence for bicarbonate transport in a unicellular red alga1

Abstract: Various physiological characteristics of photosynthesis in the unicellular red alga Porphyridium cruentum Naegeli have been investigated. The rate of photosynthesis was optimal at 25° C and pH 7.5 and was not inhibited by 21% oxygen over a temperature range of 5 to 35° C. Kinetics of whole cell photosynthesis as a function of substrate concentration gave a K1/2, (CO2) of 0.3 μM. CO2 compensation point, measured in a closed system at pH 7.5, was a constant 6.7 mL · L−1 over the temperature range 15 to 30° C and was unaffected by O2 concentration. Whole cell photosynthesis, measured in a closed system at alkaline pH, showed that the rates of oxygen evolution were greatly in excess of the rate of CO2 supply from the spontaneous dehydration of HCO3− in the medium. This indicates that bicarbonate is utilized by the cell to support this photosynthetic rate. These physiological characteristics of Porphyridium cruentum are consistent with the hypothesis that this alga transports bicarbonate across the plasmalemma.

Organisation and dissipation in economic systems

Abstract: This paper examines physical aspects of economic activity, particularly the relationship between economic ‘organisation’ and energy use. The properties of general dissipative systems are explored and the possibility of such systems becoming more organized over time is examined with reference to the second law of thermodynamics and the ‘evolutionary arrow of time’. It is argued that if a physical viewpoint is taken, economies can be considered as self-organizing dissipative systems. Measures of organization and dissipation are proposed and empirical analysis indicates that organization and energy dissipation increase together for economic systems, and there is weaker evidence that energy ‘efficiency’ also increases with organization.

Ultrastructural studies on the cellular response of fish hosts following experimental infection with the plerocercoid of Ligula intestinalis (Cestoda: Pseudophyllidea).

Abstract: With the exception of gudgeon (Gobio gobio) infection of cyprinid fish with the plerocercoid of Ligula intestinalis is associated with a host-tissue response. The nature and specificity of this response has been investigated using transplantation techniques. In roach there is an intense cellular response to implanted Sepharose, Spurr's resin and L. intestinalis, irrespective of donor host species. However, tegument damage only occurs in gudgeon-Ligula and cultured ro&ch-Ligula which has been exposed to gudgeon-plasma. L1 and L2 cell types predominate within the cellular response. Once the host leucocytes have breached the tegument, they migrate over the basal lamina and penetrate into the sub-tegumental region. In gudgeon an intense cellular attack occurs against Sepharose, Spurr's resin, ro&ch-Ligula and cultured gudgeon-Ligula which had been implanted directly or exposed to roach plasma. Tegument damage only occurs in the latter. In contrast, neither direct implantation of gudgeon-Ligula nor cultured roach-Ligula which has been exposed to gudgeon plasma evokes a cellular response. It is suggested that in these two instances, as in natural infections of gudgeon, protective host proteins may be absorbed onto the surface of the parasite.