Showing papers by "University of Bath published in 1994"
TL;DR: A neglected aspect of Data Envelopment Analysis: cross-efficiency is examined, and an intuitive understanding of cross- efficiency is ground in the concept of peer-appraisal, as opposed to self-appRAisal implied by simple efficiency.
Abstract: In this paper we examine a neglected aspect of Data Envelopment Analysis: cross-efficiency. We develop the concept of cross-efficiency in a number of new directions. We ground an intuitive understanding of cross-efficiency in the concept of peer-appraisal, as opposed to self-appraisal implied by simple efficiency, and discuss the relative merits of each. We also present mathematical formulations of, and intuitive meanings for three possible implementations of aggressive and benevolent cross-efficiency. We have implemented two of these formulations in computer programs; their performance is compared empirically on a real data set. Finally, we suggest practical uses for cross-efficiency, illustrated with reference to the same data set.
1,127 citations
TL;DR: In this article, the application of gradient-corrected exchange-correlation functionals in total energy calculations using a plane-wave basis set is discussed. But, the usual form of the exchange correlation potential includes gradients whose calculation requires the use of a high-quality representation of the density which is computationally expensive in both memory and time.
Abstract: The application of gradient-corrected exchange-correlation functionals in total-energy calculations using a plane-wave basis set is discussed. The usual form of the exchange-correlation potential includes gradients whose calculation requires the use of a high-quality representation of the density which is computationally expensive in both memory and time. These problems may be overcome by defining an exchange-correlation potential for the discrete set of grid points consistent with the discretized form of the exchange-correlation energy that is used in Car-Parrinello-type total-energy calculations. This potential can be calculated exactly on the minimum fast-Fourier-transform grid and gives improved convergence and stability as well as computational efficiency.
906 citations
TL;DR: In this article, the various types of corporate entrepreneurship (individual managers, business renewal and Schumpeterian or industry, leadership) share five "bundles" of attributes, and external and internal triggers for change are examined for a sample of 10 firms in 4 European industries.
Abstract: This paper demonstrates how the various types of corporate entrepreneurship–individual managers, business renewal and Schumpeterian, or industry, leadership–share five ‘bundles’ of attributes. Each type can exist in one firm, though at different times as the common attributes change their role and relative importance. External and internal triggers for change are examined for a sample of 10 firms in 4 European industries. The data suggest a provocative conclusion: troubled firms in hostile environments can shed past behaviors, adopt policies fostering entrepreneurship and accumulate innovative resource bundles that provide a platform on which industry leadership can be built.
823 citations
TL;DR: In this paper, computer simulation techniques are used to model the surfaces of ceria, paying special attention to the effects of surface structures and energetics on catalytic activity, and the results show that the three low energy surfaces are the (111), (110) and (310) with the first of these three being the most stable.
480 citations
Book•
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TL;DR: This chapter discusses Traditional, Modern and Neo-Modern Death, as well as Stories and Meta-stories, and Systems for Listening, which addresses expectations and Assumptions of the listening community.
Abstract: Talking about death is now fashionable, but how should we talk? Who should we listen to - priests, doctors, cousellors, or ourselves? Has psychology replaced religion in telling us how to die? This provocative book takes a sociological look at the revival of interest in death, focusing on the hospice movement and bereavement counselling. It will be required reading for anyone interested in the sociology of death and caring for the dying, the dead or bereaved.
456 citations
01 Apr 1994
TL;DR: A new method of enhancing fingerprint images is described, based upon nonstationary directional Fourier domain filtering, which leads to significant improvements in the speed and accuracy of the AFIS.
Abstract: A new method of enhancing fingerprint images is described, based upon nonstationary directional Fourier domain filtering. Fingerprints are first smoothed using a directional filter whose orientation is everywhere matched to the local ridge orientation. Thresholding then yields the enhanced image. Various simplifications lead to efficient implementation on general-purpose digital computers. Results of enhancement are presented for fingerprints of various pattern classifications. A comparison is made with the enhancement used within the automated fingerprint identification system (AFIS) developed by the UK Home Office. Use of the proposed enhancement method leads to significant improvements in the speed and accuracy of the AFIS.
367 citations
TL;DR: Photolabelling results suggest that the glucose transporter translocation process is dependent upon PtdIns 3-kinase activity, which is a key intermediate in insulin signalling of glucose-transport stimulation.
Abstract: Wortmannin is a potent and reversible inhibitor of insulin-stimulated PtdIns 3-kinase activity in 3T3-L1 cells (IC50 = 2.6 +/- 0.8 nM). Wortmannin inhibits the PtdIns 3-kinase activity which is precipitated with antibodies against insulin receptor substrate 1 and against the alpha-p85 subunit of PtdIns 3-kinase. These observations suggest that wortmannin inhibits at the p110 catalytic subunit of PtdIns 3-kinase. Insulin stimulation of glucose transport in permeabilized 3T3-L1 cells is also inhibited by wortmannin (IC50 = 6.4 +/- 1.4 nM). Wortmannin did not inhibit basal glucose transport activity. The close similarity of the IC50 values for wortmannin inhibition of insulin-stimulated PtdIns 3-kinase and glucose transport activities suggests that the PtdIns 3-kinase is a key intermediate in insulin signalling of glucose-transport stimulation. The wortmannin inhibitory effect on transport is associated with a reduction in the cell-surface, but not the total cellular, levels of both GLUT1 and GLUT4 glucose transporter isoforms that are accessible to the cell-impermeant photolabel, ATB-BMPA. These photolabelling results suggest that the glucose transporter translocation process is dependent upon PtdIns 3-kinase activity. The stimulatory effect of guanosine 5'-[gamma-thio]triphosphate (GTP gamma S) on glucose transport activity in permeabilized cells is only partially blocked by concentrations of wortmannin that completely inhibit the stimulatory effect of insulin. The residual stimulatory effect of GTP gamma S that occurs in the presence of wortmannin suggests that at least part of the GTP gamma S effect is mediated at a signalling site that is downstream of the site at which wortmannin inhibits the insulin stimulation of PtdIns 3-kinase and glucose transport activities.
350 citations
01 Jan 1994
TL;DR: In this article, the ingress problem in rotor-stator systems is addressed, including basic equations, Laminar flow over a single disc, Turbulent flow over one disc, heat transfer from one disc to another, and a superposed flow.
Abstract: This book addresses rotor-stator systems. Topics covered include: Basic Equations; Laminar flow over a single disc; Turbulent flow over a single disc; Heat transfer from a single disc; Rotor-stator systems with no superposed flow; Rotor-stator systems with a superposed flow; Heat transfer in rotor-stator systems; and Sealing rotor-stator systems: The ingress Problem.
332 citations
TL;DR: Both osteosarcoma cell lines proliferated more rapidly than osteoblast-like cells with HOS cells exhibiting the shortest doubling time and short term, serum-free cell adhesion assays showed that the three cell types adhered in a saturation manner to collagen I, fibronectin, and laminin.
315 citations
TL;DR: Taguchi methods are described for optimisation of the PCR because they revealed the effects and interactions of specific reaction components simultaneously using just a few reactions, negating the need for extensive experimental investigation.
Abstract: Taguchi methods are used widely as the basis for development trials during industrial process design. Here, we describe their suitability for optimisation of the PCR. Unlike conventional strategies, these arrays revealed the effects and interactions of specific reaction components simultaneously using just a few reactions, negating the need for extensive experimental investigation. Reaction components which effected product yield were easily determined. In addition, this technique was applied to the qualitative investigation of RAPD-PCR profiles, where optimisation of the size and distribution of a number of products was determined.
308 citations
TL;DR: In this paper, a new way to tailor the crystal chemistry of inorganic solids involves molecular recongnition between two-dimensional organic templates and embryonic inorganic aggregates.
Abstract: A new way to tailor the crystal chemistry of inorganic solids involves molecular recongnition between two‐dimensional organic templates and embryonic inorganic aggregates. Langmuir monolayers adopted as model surfaces offer opportunities for molecular engineering of the template. The Figure shows one example of oriented nucleation of vaterite under octadecylamine monolayers. (Figure Presented.) Copyright © 1994 Verlag GmbH & Co. KGaA, Weinheim
01 Mar 1994
TL;DR: In this article, a time dependent dynamic resistance representation of the primary arc is proposed with emphasis on an empirical approach which is used to determine the parameters concerned In particular, significant improvements have been made to the dynamic conducting characteristic of secondary arc models.
Abstract: A realistic simulation of fault arcs is extremely important in the successful design and development of alternative and improved transmission system equipment such as adaptive auto-reclosure and novel protection schemes It is also particularly important in relation to the design of single pole switched systems This paper discusses, in some detail, techniques that have been developed to model fault arcs more realistically than has been achieved hitherto A time dependent dynamic resistance representation of the primary arc is proposed with emphasis on an empirical approach which is used to determine the parameters concerned In particular, significant improvements have been made to the dynamic conducting characteristic of secondary arc models The paper concludes with a presentation of some interesting studies relating to typical 400 kV single circuit and double circuit systems when the new are models are incorporated into the electromagnetic transients program (EMTP)
TL;DR: In this paper, a two-dimensional finite-element simulator was used to examine previously reported studies of propane and carbon monoxide combustion in excess oxygen, and the results from the simulations are much higher than results which have been reported in the literature for experimental work.
TL;DR: The active site has many features in common with other viral and bacterial neuraminidases but, uniquely, has an essential Ca2+ ion which plays a crucial structural role.
Journal Article•
TL;DR: The Utah Population Database allows examination of the genetic relationships among the 35.7% of all cancer cases in the state that have genealogical records to measure familial clustering of cancer.
Abstract: The Utah Population Database allows examination of the genetic relationships among the 35.7% of all cancer cases in the state that have genealogical records. Familial clustering of cancer is measured by the Genealogical Index of Familiality and is examined by site, and within site by age of onset, histology, and gender. Most cancer sites examined show excess familiality for all cases considered together. Subsets of individuals with certain characteristics showed unusually high levels of familial clustering, specifically lymphocytic leukemias and especially chronic lymphocytic leukemia, lobular breast cancer, early lip cancer, early melanoma, and female lung cancers of alveolar/adenoma histology. These may represent characteristics of the most penetrant forms of inherited susceptibilities, those which are enhanced by environmental factors, chance aggregations, rare inherited syndromes, or a combination of these factors.
TL;DR: In this article, a Hamiltonian formulation of the water-wave problem is presented, in which the non-local Dirichlet-Neumann operator appears explicitly in the Hamiltonian, and a straightforward transformation theory describes the relationship between the classical symplectic structure appearing in the water wave problem and the various non-classical symplectic structures that arise in long wave approximations.
TL;DR: In this paper, a study of the fatigue behavior of a laminate of the T800/5245 composite system was presented, where the fatigue response in repeated tension, repeated compression, and mixed tension-compression was determined at constant stress levels over a wide range of R values, and the results were analyzed in terms of constant-life diagrams of the kind that can be used to provide design data.
TL;DR: In this article, the authors introduce a new multidimensional concept of the innovativeness of organizations and develop an approach for its measurement involving a cross-section of innovations adopted by multiple organizations in multiple industries.
Abstract: Presents research which: introduces a new multidimensional concept of the innovativeness of organizations; develops an approach for its measurement involving a cross‐section of innovations adopted by multiple organizations in multiple industries; identifies different economic, organizational/managerial, industry specific and governmental/legislation and infrastructure factors which influence the various dimensions of the innovativeness of organizations; and suggests how this alternative approach can be used for the better understanding of the concept of the innovativeness of organizations and its applied context within the marketing discipline.
TL;DR: In this paper, the potential energy surface of the Cu(100) surface was analyzed for two extreme dissociation geometries and a very marked surface corrugation was found.
Abstract: First-principles calculations of the potential energy surface for ${\mathrm{H}}_{2}$ dissociation on the Cu(100) surface are presented. The height of the transition state above the surface and energy barrier are mapped over the surface. A very marked surface corrugation is found. Normal mode frequencies at the transition state for two extreme dissociation geometries suggest that zero point energy contributes little to surface corrugation. The local density approximation predicts a zero minimum barrier. Gradient corrections greatly increase the barrier height, but have little effect on the surface corrugation.
TL;DR: The resulting materials represent replicas of the microemulsion architecture, but the pore sizes are incommensurate, suggesting that secondary modifications in the bicontinuous microstructure occur during crystal growth.
Abstract: The chemical construction of organized architectures is an important aspect of innovative materials synthesis. Bicontinuous water-filled microemulsions can be used as preorganized systems for the fabrication of crystalline calcium phosphate materials with extended reticulated microstructures. These macroporous materials are formed by mineralization reactions located within the interconnecting water channels of the bicontinuous network. The resulting materials represent replicas of the microemulsion architecture, but the pore sizes are incommensurate, suggesting that secondary modifications in the bicontinuous microstructure occur during crystal growth. Synthetic macroporous calcium phosphates could have uses in biomaterial implants.
TL;DR: The three-dimensional structural comparison of thermophilic and mesophilic citrate synthases has permitted catalytic and substrate-binding residues to be tentatively assigned in the archaeal, thermophile enzyme, and has identified structural features that may be responsible for its thermostability.
TL;DR: In this article, the basic physical and magnetic properties of Fe and Co based amorphous wires are summarised, together with post-production treatments used to modify the properties of the as-quenched alloys.
TL;DR: The following servomechanism problem is solved: Determine a l-universal adaptive strategy to control the output to track any reference signal in W 1,∞, with tracking error asymptotic to a ball of arbitrary prescribed radius λ >0.
TL;DR: The crystal structure of a toxin associated with toxic-shock syndrome, TSST-1, which is a microbial superantigen, has been determined at 2.5 Å resolution and the topology is similar to the structure reported for thesuperantigen staphylococcal enterotoxin B4.
Abstract: SUPERANTIGENS stimulate T cells bearing particular T-cell receptor Vβ sequences1,2, so they are extremely potent polyclonal T-cell mitogens. T-cell activation is preceded by binding of superantigens to class II major histocompatibility complex (MHC) molecules3. To further the structural characterization of these interactions, the crystal structure of a toxin associated with toxic-shock syndrome, TSST-1, which is a microbial superantigen, has been determined at 2.5 A resolution. The N- and C-terminal domains of the structure both contain regions involved in MHC class II association; the C-terminal domain is also implicated in binding the T-cell receptor. Despite low sequence conservation, the TSST-1 topology is similar to the structure reported for the superantigen staphylococcal enterotoxin B4. But TSST-1 lacks several of the structural features highlighted as central to superantigen activity in the staphylococcal enterotoxin B and we therefore reappraise the structural basis of superantigen action.
TL;DR: The possibility of ‘induced fit’ as a common mechanism for antigen-antibody interactions has been raised, and a molecular basis for hapten and protein cross-reactivity proposed, and these recent contributions to the field provided exciting new insights.
TL;DR: With its nanodimensional biomimetic protein cage as a rigid, convenient matrix for complexing a plethora of bioactive substances, magnetoferritin may provide a novel template for specific targeting of selected cellular sites.
Abstract: A protein-encaged superparamagnetic iron oxide has been developed and characterized by using horse spleen apoferritin as a novel bioreactive environment. The roughly spherical magnetoferritin molecules, 120 A in diameter, are composed of a monocrystalline maghemite or magnetite core 73 A +/- 14 in diameter. Except for the additional presence of iron-rich molecules of higher molecular weight, the appearance and molecular weight (450 kd) of magnetoferritin are identical to that of natural ferritin; the molecules are externally indistinguishable from their precursor, with a pI (isoelectric point) in the range 4.3-4.6. The measured magnetic moment of the superparamagnetic cores is 13,200 Bohr magnetons per molecule, with T1 and T2 relaxivities (r1 and r2) of 8 and 175 L.mmol-1 (Fe).sec-1, respectively, at body temperature and clinical field strengths. The unusually high r2/r1 ratio of 22 is thought to arise from ideal core composition, with no evidence of crystalline paramagnetic inclusions. T2 relaxation enhancement can be well correlated to the field-dependent molecular magnetization, as given by the Langevin magnetization function, raised to a power in the range 1.4-1.6. With its nanodimensional biomimetic protein cage as a rigid, convenient matrix for complexing a plethora of bioactive substances, magnetoferritin may provide a novel template for specific targeting of selected cellular sites.
TL;DR: A mathematical analysis shows that the subcellular trafficking of GLUT4 in isolated rat adipose cells and 3T3-L1 adipocytes exhibits many of the properties observed in regulated secretory processes and neurosecretion, but that a 3-pool model, with two intracellular compartments, can simulate these properties.
01 Sep 1994
TL;DR: In this article, a new numerical technique for evaluating power system frequency from either a voltage or current signal is presented, which uses discrete time values of the input signal, taken at a fixed sampling rate, to provide an estimate of power system frequencies accurate to within typically 0.001 Hz.
Abstract: A new numerical technique for evaluating power system frequency from either a voltage or current signal is presented. The technique uses discrete time values of the input signal, taken at a fixed sampling rate, to provide an estimate of power system frequency accurate to within typically 0.001 Hz. The technique is shown to be capable of tracking frequency under dynamic power systems conditions and is immune to the effect of harmonics. It is further shown that the algorithm can be easily adapted to process three-phase signals such that the positive phase sequence component can be utilised thus increasing the reliability of the measurement under fault conditions.
Journal Article•
TL;DR: The gene expression and secretion patterns for the chemokines interleukin-8 and monocyte chemoattractant protein-1 in cytokine- and lipopolysaccharide-treated cultured human lung microvascular endothelial cells (HLE) are determined and suggest that the regulation of IL-8
Abstract: The elicitation of leukocytes from the circulation to inflamed tissue depends on the activation of both the leukocyte and endothelial cell. In this study we determined the gene expression and secretion patterns for the chemokines interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) in cytokine- and lipopolysaccharide (LPS)-treated cultured human lung microvascular endothelial cells (HLE). HLE constitutively expressed low levels of MCP-1 and IL-8. Treatment of HLE with a variety of cytokines and LPS up-regulated both IL-8 mRNA expression and release of immunoreactive IL-8 with an order of potency tumor necrosis factor-alpha (TNF-alpha) >> IL-1 alpha > LPS, whereas interferon-gamma (IFN-gamma) had no effect on IL-8 mRNA or antigenic levels. However, IFN-gamma, in combination with high doses of IL-1 alpha, resulted in a synergistic increase in IL-8 generation. MCP-1 gene expression and secretion was induced in a dose-dependent manner after IL-1 alpha, TNF-alpha, IFN-gamma, and LPS activation of HLE. IL-1 alpha was the most potent inducer of MCP-1 generation and LPS was relatively ineffective. IFN-gamma, in combination with low doses of IL-1 alpha, resulted in a synergistic increase in MCP-1 generation by HLE. These results demonstrate that although IL-8 and MCP-1 generation by HLE occurs on cytokine treatment, the relative ability of a given cytokine to elicit IL-8 generation is not directly parallel to effects on MCP-1 generation. These data suggest that the regulation of IL-8 and MCP-1 expression exhibit significant differences in their mechanisms. Such differences in the expression of specific chemokines may explain the specific appearance of various leukocytes at sites of inflammation and injury. These data also directly demonstrate that the lung microvascular endothelium contribute to the cytokine network of the lung, with the ability to respond to locally generated cytokines and to produce potent mediators of the local inflammatory response.