Showing papers by "University of Bath published in 1980"
TL;DR: In this paper, a buyer-seller relationship is considered as a process through time, it is based on ideas from the IMP Project, and the process of establishment and development of relationship over time by considering stages in revolution.
Abstract: Notes buyer‐seller interdependence is crucial to industrial marketing — industrial firms establish buyer‐seller relationships of the close kind and long term. Examines buyer‐seller nature in industrial markets by considering development as a process through time, it is based on ideas from the IMP Project. Analyses the process of establishment and development of relationship over time by considering stages in revolution. Notes also that this process described herein does not argue the inevitability of relationship development. Discusses the pre‐relationship stage: the early stage; the development stage; the long‐term stage; and the final stage with points to debate. Describes how the development of buyer‐seller relationships can be seen as a process in terms of: the increasing experience of the two companies; reduction in their uncertainty and the distance between them; growth of both actual and perceived commitment; formal and informal adaptation to each other and the investments and savings involved. Fin...
1,416 citations
01 Jan 1980
TL;DR: A vector identity associated with the Dirichlet tessellation is proved as a corollary of a more general result as mentioned in this paper, which has applications in interpolation and smoothing problems in data analysis.
Abstract: A vector identity associated with the Dirichlet tessellation is proved as a corollary of a more general result. The identity has applications in interpolation and smoothing problems in data analysis, and may be of interest in other areas.
454 citations
223 citations
TL;DR: This chapter explores the usage of decaying wood as a vehicle for understanding natural fungal populations and communities by focusing on the decay in dead or moribund natural woody substrata such as stumps, logs, trunks, and branches.
Abstract: Publisher Summary Decaying wood presents unique opportunities for those interested in growth and interaction of fungi with one another to form populations and communities in natural substrata. This is because decaying wood is a spatially defined, bulky resource in which many of the fungi—especially those causing decay—frequently occur as single colonies, each occupying considerable volumes. Wood becomes decayed under a wide range of circumstances—namely, within the living tree, after felling or pruning in dead trunks, logs, stumps, and branches, and at almost any stage during its conversion and subsequent varied use by man. The process and rate of decay is generally influenced by innumerable factors—including the type of wood, its moisture content, its nitrogen content, treatment with preservatives, and temperature. This chapter explores the usage of decaying wood as a vehicle for understanding natural fungal populations and communities. The chapter focuses on the decay in dead or moribund natural woody substrata such as stumps, logs, trunks, and branches rather than in living trees or with timber converted for use by man and which have been variously treated or preserved.
202 citations
TL;DR: The present review is concerned exclusively with ADP-ribosylation carried out in eukaryotic nuclei and will concentrate on the large amount of data that has emerged subsequent to the publication of other reviews.
Abstract: ADP-ribosylation can be defined as the postsynthetic modification of protein by the covalent attachment of the ADP-ribose moiety of NAD+. ADP-ribosylation of elongation-factor Tu is responsible for the inhibition of protein synthesis by both diptheria and Pseudomonas aeroginosa toxins (Hilz & Stone, 1976). The activation of membrane adenylate cyclase by cholera toxin is thought to occur by ADP-ribosylation of the adenylate cyclase-associated GTP binding protein (Gill & Meren, 1978). It has also been proposed as a mechanism by which Escherichia coli RNA polymerase activity is modified during bacteriophage T4 infection (Goff, 1974; Rohrer et al., 1975; Skorko et al., 1977). Coliphage N4 has also been reported to contain an intrinsic ADP-ribosyltransferase activity (Pesce et al., 1976). ADP-ribosyltransferase activity is also present in the mitochondria and nuclei of all eukaryotic organisms examined to date. The field of ADP-ribosylation has been comprehensively reviewed by Sugimura (1973), Hilz & Stone (1976) and Hayaishi & Ueda (1977). The present review is concerned exclusively with ADP-ribosylation carried out in eukaryotic nuclei and will concentrate on the large amount of data that has emerged subsequent to the publication of other reviews. The enzyme responsible for ADP-ribosylation in nuclei is termed poly(ADP-ribose) synthetase or polymerase; the name is derived from the fact that, unlike other ADP-ribosyltransferases, the enzyme is capable of synthesizing a protein-bound homopolymer of ADP-ribose, poly(ADP-ribose) (Chambon et al., 1966; Reeder et al., 1967; Fujimura et al., 1967). NAD is cleaved at the nicotinamide-ribose bond (bond energy 34 kJ/mol) and the ADP-ribose moiety transferred to either a nuclear protein or a protein-bound ADP-ribose molecule. The polymer thus formed is degraded by another nuclear enzyme, poly(ADP-ribose) glycohydrolase, producing the free monomeric form of ADP-ribose (Miwa & Sugimura, 1971) (Fig. 1 ) .
194 citations
TL;DR: Evidence is presented which shows thatSelf-incompatibility in diploid Lolium perenne is determined, as in other self-incompatible grasses that have been investigated, by two multi-allelic genes and that control of the pollen phenotype is gametophytic.
Abstract: An analysis of the data from six families of full-sibs shows that one of the incompatibility genes in perennial ryegrass is linked in its inheritance to the gene, PGI-2, which codes for the enzyme phosphoglucoisomerase. In the light of this evidence, we define S as the gene that is linked to PGI-2. The best estimate of the frequency of recombination between PGI-2 and S is p = 0·1538 ± 0·0252.
186 citations
TL;DR: In the last decade the awareness of environmental problems has not only increased dramatically, but has taken on a new political significance as discussed by the authors, with the emergence of new social groups, new interests and new values which cut across traditional class-based alignments and cleavages.
Abstract: There has been increasing interest in recent years in the possibility of fundamental changes in the political system, with the emergence of new social groups, new interests and new values which cut across traditional class-based alignments and cleavages. Moreover, in recent decades, there has been a marked increase in direct action, and the growth of outsider politics, a decline in partisan support for die traditional parties, and other indications of a loss of legitimacy.' Such indications of strain and stress take on a special significance with the possibility that industrial societies, which have relied so heavily on policies of sustained and rapid economic growth for maintaining a broad spearum of consensus and support, may be facing special challenges with intransigent problems of unemployment and inflation, exacerbated by increasing shortages of materials and energy.^ The environmentalist movement provides an important case study and focus for exploring such issues. In the last decade the awareness of environmental problems has not only increased dramatically, but has taken on a new political significance. Environmentalist groups have been at the centre of protest, locally and nationally, against motorways, airports and dams, and have vigorously opposed the nuclear programme in a number of countries. And in the last few years, newly formed 'ecology parties' have captured a sizeable proportion of the votes at elections. The significance of the environment has shifted from a preoccupation with the preservation of the countryside, historic buildings and local amenities, to become the focus for radical protest. Above all, environmentalists have challenged the central values and ideology of industrial society. It is with this dimension of the environmentalist movement that this analysis is concerned. Is environmental protest indicative of a fundamental
172 citations
TL;DR: In this article, a momentum polarization was introduced to cope with density variations in a way that exactly parallels the stress polarization's correspondence with variations in moduli, and the authors derived an asymptotic formula for scattering cross-sections of penny-shaped cracks, rigid circular discs and rigid needles.
Abstract: Scattering problems in elastodynamics are formulated in terms of integral equations, whose kernels are obtained from the Green's function for a comparison body. The comparison body will usually be taken as homogeneous and elastic in applications but, at least formally, there is no bar to its being inhomogeneous, viscoelastic and non-local. The novel feature of the formulation is the introduction of a “momentum polarization” to cope with density variations in a way that exactly parallels the stress polarization's correspondence with variations in moduli. To illustrate the use of the equations, scattering by an ellipsoidal inhomogeneity in a generally anisotropic matrix is studied in the Rayleigh limit and an asymptotic formula for its scattering cross-section is given. Detailed results are presented for a spheroidal inhomogeneity in an isotropic matrix, with explicit limiting forms for the scattering cross-sections of penny-shaped cracks, rigid circular discs and rigid needles.
137 citations
TL;DR: In this paper, the Levine-Mark theory of the surface states of ionic insulators was tested for oxides, and the numerical values of the parameters appropriate to the oxides were evaluated by using experimental data on bulk excitons.
Abstract: Ultra-violet (u.v.) diffuse reflectance spectra of microcrystalline MgO, CaO, SrO and BaO reveal bands at energies below those of bulk excitonic transitions. Correlation of the spectra permit three distinctive absorptions (I, II, III) to be identified, each with similar characteristics in the respective oxides. The absorptions are ascribed to surface states, and the transitions have the characteristics of excitons. Excitons II and III obey the Mollwo–Ivey relation typical of bound excitons, but excition I with the highest energy of transition behaves similarly to a free exciton of the bulk. The four oxides are isostructural and ionic. The Levine–Mark theory of the surface states of ionic insulators, not hitherto tested for oxides, is examined. The numerical values of the parameters appropriate to the oxides are evaluated by using experimental data on bulk excitons. It is shown that the theory accounts satisfactorily for the energies of exciton I in MgO, CaO and SrO on the basis that it is an exci...
136 citations
TL;DR: In this article, the same range of resins were used as a matrix material for a series of composites reinforced with carbon, glass and aromatic polyamide fibres, and the composites were unidirectionally reinforced, having been manufactured by pultrusion, and were compression tested in the fibre direction.
Abstract: The compression behaviour of a series of polyester resins of various compositions and in different states of cure has been investigated. Their mechanical characteristics having been established, the same range of resins was then used as a matrix material for a series of composites reinforced with carbon, glass and aromatic polyamide fibres. The composites were unidirectionally reinforced, having been manufactured by pultrusion, and were compression tested in the fibre direction after a series of experiments to assess the validity of a simple testing procedure. “Rule of Mixtures” behaviour occurred in glass-polyester composites up to limiting volume fractions (V
f) of 0.31 for strength and 0.46 for elastic modulus, the compression modulus being equal to the tensile modulus, and the apparent fibre strength being in the range 1.3 to 1.6 GPa at this limiting V
f. At a V
f of 0.31 the strengths of reinforced polyesters were proportional to the matrix yield strength, σ
my, and their moduli were an inverse exponential function of σ
my. For the same matrix yield strength a composite with an epoxy resin matrix was stronger than polyester based composites. At V
f=0.30, Kevlar fibre composites behaved as though their compression modulus and strength were much smaller than their tensile modulus and strength, while carbon fibre composites were only slightly less stiff and weaker in compression than in tension. The compression strengths of the polyester resins were found to be proportional to their elastic moduli.
134 citations
TL;DR: The integral equation formulation given in the accompanying paper (Part I) is applied to the study of plane waves propagating in a composite material comprising a possibly anisotropic elastic matrix containing aligned elastic inclusions, positioned randomly as mentioned in this paper.
Abstract: The integral equation formulation given in the accompanying paper (Part I) is applied to the study of plane waves propagating in a composite material comprising a possibly anisotropic elastic matrix containing aligned elastic inclusions, positioned randomly. An asymptotic solution is given for waves of low frequency. To lowest order, the equations are related closely to those which define the static overall moduli and it is shown that low frequency waves propagate as though the material were homogeneous, with elastic moduli equal to the static overall moduli and density equal to the mean density of the composite. Estimates of the overall moduli that follow from the formulation coincide, for a certain class of composites, with estimates obtainable from the Hashin-Shtrikman variational principle; explicit bounds for the overall moduli of bodies containing aligned penny-shaped cracks, aligned rigid discs and aligned rigid needles follow as by-products of the analysis. Continuing the perturbation solution generates an imaginary term in the series denning the wave number of any one of the plane waves; this corresponds to attenuation of the mean wave by scattering. The lowest order approximation to the attenuation coefficient is found explicitly. It involves the product of the concentration of the inclusions, a factor containing an integral of the pair distribution function and a concentration-dependent term that reduces exactly to one of the scattering cross-sections discussed in Part I in the low concentration limit. Examples show that, at any given frequency, attenuation increases initially with concentration, attains a maximum and then declines as concentration increases further.
TL;DR: The chapter provides evidence that silkmoth eclosion behavior is initiated directly by eClosion hormone, and shows how one is integrated with the other.
Abstract: Publisher Summary This chapter presents a review that aims to bring together what is known of the physiology of ecdysis with what is known of the behavior of ecdysing insects and shows how one is integrated with the other. Ecdysial behavior is probably largely programmed within the CNS, but once initiated the details of its performance may be more or less influenced by sensory feedback according to the species, and which part of the behavior is being considered. The exceptional stereotypy of the abdominal movements involved in the preeclosion and eclosion behavior of H. cecropia and the confinement of eclosion to a narrow, temporal “gate” by a circadian clock in the brain are key factors that led to the discovery of the role of the eclosion hormone in initiating eclosion behavior. The chapter provides evidence that silkmoth eclosion behavior is initiated directly by eclosion hormone. H. cecropia and A. pernyi emerge from the pupal cuticle only at a particular time of day, during relatively narrow gates determined by a circadian clock. If the pharate adults are removed from their pupal cases during the few hours before the normal eclosion gate, then they continue to show predominantly pupal behavior. In the case of A .pernyi , this is particularly striking, the peeled moth showing very little spontaneous motor activity at all. However, at the time of the normal eclosion gate, the moths go through a pantomime emergence, despite having been free of the pupal case for several hours.
DOI•
01 Jul 1980TL;DR: In this paper, the basis of a new ultra-high-speed transmission line protection scheme is described, where analogue processing is performed using charge-coupled devices to extract the fault or superimposed components impressed on a power system following a disturbance.
Abstract: The basis of a new ultra-high-speed transmission-line protection scheme is described. Analogue processing is performed using charge-coupled devices to extract the fault or superimposed components impressed on a power system following a disturbance. The new arrangement is designed for use in conjunction with carrier blocking communication equipment and tripping times of typically 2 to 4 ms are shown to be feasible for most faults. The results of an cxtensive series of laboratory tests are given and the paper concludes with a consideration of the performance of the new scheme following very high resistance single phase-to-earth faults.
TL;DR: A consultancy project which was concerned with identifying a successful future for an ailing journal is described and the use of cognitive mapping as an aid to defining the nature of a policy problem which involves conflicting and qualitative views of the problem is discussed.
Abstract: This paper describes and discusses a consultancy project which was concerned with identifying a successful future for an ailing journal. The paper emphasises that part of the project which involved problem construction and discusses the use of cognitive mapping as an aid to defining the nature of a policy problem which involves conflicting and qualitative views of the problem.
TL;DR: Calculation of volume of xylem fluids indicated that endo-PL activity in vessels of infected stems was comparable to that attained in cultures containing polygalacturonide substrates, and the significance of enzymic degradation or alteration of pit membranes is discussed in relation to the induction of water stress.
Abstract: High endo-pectin lyase (endo-PL) activity occurred in vascular tissue of susceptible tomato cuttings (cv. Gem S.) 3 days after infection by Verticillium albo-atrum and before symptoms appeared. The enzyme also occurred in a near isogenic resistant cultivar (Gem R.) but at much lower levels. Endo-polygalacturonase (endo-PG) was also found but only at slightly above endogenous levels. Activities of both enzymes decreased markedly as symptoms developed. In stem segments infiltrated with propagules of V. alto-atrum, endo-PL was the only cell wall-degrading enzyme with increased activity. Similar and high levels were detected after 3 to 4 days in vascular tissue excised from Gem R and Gem S stems, and were related to inoculum density. Calculation of volume of xylem fluids indicated that endo-PL activity in vessels of infected stems was comparable to that attained in cultures containing polygalacturonide substrates. In root-inoculated plants (cv. Craigella) endo-PG increased slightly at first but later there was no increase in activity of any wall-degrading enzyme, although vessels contained gels and degraded pit membranes. Disease symptoms, including vascular gels, were reproduced by supplying stems and leaves with partially purified endo-PL and endo-PG so that they contained amounts similar to those detected in xylem of infected plants. The significance of enzymic degradation or alteration of pit membranes is discussed in relation to the induction of water stress.
01 Jan 1980
TL;DR: In this paper, the original set of variables are transformed to a new set of uncorrelated variables called principal components, which are linear combinations of the original variables and are derived in decreasing order of importance so that the first principal component accounts for as much as possible of the variation in the original data.
Abstract: In order to examine the relationships among a set of p correlated variables, it may be useful to transform the original set of variables to a new set of uncorrelated variables called principal components. These new variables are linear combinations of the original variables and are derived in decreasing order of importance so that, for example, the first principal component accounts for as much as possible of the variation in the original data. The transformation is in fact an orthogonal rotation in p-space.
TL;DR: Production of the prostacyclin‐like material by the myometrium was similar at weeks 15 and 38 of pregnancy but a 4‐fold increase in synthesis had occurred by 40 weeks, and it is suggested this increase may be important for parturition.
TL;DR: In this article, temperature-programmed thermal decomposition of α-manganese oxyhydroxide has been studied between 20 and 670°C under vacuum and under a low pressure (10 Torr) of oxygen.
TL;DR: Differential rates of 14C-amino acid incorporation suggest that glyphosate depleted the phenylalanine protein precursor pool with resultant inhibition of protein synthesis, as evidenced by a rapid decline in the level of 'soluble' protein.
Abstract: Glyphosate promoted the activity of phenylalanine ammonia lyase (PAL) in both single node rhizome buds of Agropyron repens and root tips of wheat seedlings, in the latter case correlating inversely with decline in respiratory activity. Differential rates of 14C-amino acid incorporation suggest that glyphosate depleted the phenylalanine protein precursor pool with resultant inhibition of protein synthesis, as evidenced by a rapid decline in the level of 'soluble' protein. Promotion of PAL is assumed to occur by derepression through decline in end-product levels. Activities of shikimate:NADP oxidoreductase (SORase), chorismate mutase, and polyphenol oxidase (PPO) were also elevated, but to lesser extents than for PAL.
TL;DR: In this article, the second and third-order elastic stiffness tensors of amorphous arsenic (a-As) were measured by the pulse echo overlap overlap and pulse superposition techniques.
Abstract: The hydrostatic and uniaxial pressure and the temperature dependences of the ultrasonic wave velocities in bulk amorphous arsenic (a-As) have been measured by the pulse echo overlap and pulse superposition techniques. The results provide the first complete set of components of the second- and third-order elastic stiffness tensors of an amorphous element. The ultrasound velocities, and elastic stiffnesses of the amorphous material are appreciably smaller than those of the crystalline, rhombohedral allotropic form. The bulk, shear and Young's moduli and the pressure derivatives of the bulk and shear moduli of a-As conform well with trends noted previously for these properties in chalcogenide glasses in terms of the average number of covalent bonds per atom. In marked contrast to the anomalous behaviour of the insulating, silica-based glasses, the pressure derivatives of the bulk and shear moduli of a-As are found to be positive, while the temperature derivatives are negative. This more normal elast...
TL;DR: In this article, a calculation of the energy bands of V2O5 is presented, and the semiconducting gap is calculated to be 2.6 eV. The method avoids the limitations and assumptions inherent in the only previous calculation of electronic structure of this material.
Abstract: A calculation of the energy bands of V2O5 is presented. The method avoids the limitations and assumptions inherent in the only previous calculation of the electronic structure of this material. The valence and conduction band structure appear to provide more convincing agreement with measured photoemission and optical properties. The semiconducting gap is calculated to be 2.6 eV.
TL;DR: Glucose transport in human erythrocytes is characterized by a marked asymmetry in the V and Km values for entry and for exit, and an allosteric pore model has been proposed to account for these characteristics.
TL;DR: Aflatoxin B1-hydroxyesters appear to be models of AFB1-8,9-oxide in that they are bacterial mutagens, stimulate unscheduled DNA synthesis in HeLa cells and react with DNA to give trans-8-9-dihydro-8(7-guanyl)-9-Hydroxy-AFB1 as the major adduct after hydrolysis.
Abstract: A number of aflatoxin B1 (AFB1) derivatives have been synthesized including 8-acyloxy- and 8-benzoyloxy-9-hydroxy-8,9-dihydro-AFB1 compounds, AFB1-8,9-diol and [3H] AFB1 labelled at the 9 position. AFB1-hydroxyesters appear to be models of AFB1-8,9-oxide in that they are bacterial mutagens, stimulate unscheduled DNA synthesis in HeLa cells and react with DNA to give trans-8,9-dihydro-8(7-guanyl)-9-hydroxy-AFB1 as the major adduct after hydrolysis. The potency of the hydroxyesters increases with ease of release of the ester grouping at position 8. Absence of the hydroxyl at position 9 gives compounds which are readily hydrolysed in water but are not biologically active. The hydroxyesters hydrolyse in water to give AFB1-diol, providing a convenient means of synthesis of this compound. Studies with AFB1-diol show that it reacts with one molecule of Tris base, probably through the ring-opened furan form, with the amino group of the Tris. Acidification results in ring closure in an analogous manner to AFB1-diol. AFB1-diol binds to DNA in vitro as well as to liver slice DNA. The compound is mutagenic towards S. typhimurium TA100 without metabolic activation. The implications of these findings are discussed in relation to the mechanisms of AFB1 carcinogenicity.
TL;DR: The glucose transport asymmetry of intact human red cells has been shown to be retained in pink erythrocyte ghosts and 3-Isobutyl-1-methylxanthine inhibits net glucose efflux in intact cells and ghosts and also net influx in cells.
TL;DR: In this article, an automatic gated-carrier pulse superposition system for high precision ultrasonic velocity measurements is described, having better stability and lower cost than previous equipment, and the necessary new integrated circuitry and the method of operation are described in detail.
TL;DR: In this paper, it was shown that the post-bifurcation solution curve connects the two bifurcation points and that the spherical configuration is regained upon further inflation.