Showing papers by "University of Bath published in 2001"

Interdependencies, trust and information in relationships, alliances and networks

Abstract: The last decade has been characterised by the increased development of cross-company relationships, alliances and more complex business networks. This paper examines fundamental concepts that relate to the needs for information, including accounting information, in these interactive structures. It considers, initially, some consequences for accounting when planning and control is to be exercised across organisational boundaries, but the main thrust of the paper is to focus on the fact that all relationships depend to some extent on trust. The interaction between trust and information in personal relationships is explored to serve as a template against which to consider whether the information needs of inter-organisational relationships are similar. Having examined information needs of business relationships in general, the analysis is developed to consider the needs of different forms of corporate alliances and then wider business networks. This paper is an attempt to create a debate on new questions that seem to be fundamental to the design of information and accounting systems. It is not claimed to have provided definitive answers, but it is proposed that the lack of a well-developed theory of the interaction between trust and information has been a fundamental gap in our knowledge.

The McKay correspondence as an equivalence of derived categories

Abstract: The classical McKay correspondence relates representations of a finite subgroup G ⊂ SL(2,C) to the cohomology of the well-known minimal resolution of the Kleinian singularity C2/G. Gonzalez-Sprinberg and Verdier [10] interpreted the McKay correspondence as an isomorphism on K theory, observing that the representation ring of G is equal to the G-equivariant K theory of C2. More precisely, they identify a basis of the K theory of the resolution consisting of the classes of certain tautological sheaves associated to the irreducible representations of G.

Highly expressed genes in yeast evolve slowly

Abstract: THE rate of protein evolution shows considerable variation among genes. This variation is thought to reflect differences in the proportion of the sequence that is critical to fulfill given functions ([Li 1997][1]), but local recombination intensity ([Williams and Hurst 2000][2]) might also have an

Zebrafish colourless encodes sox10 and specifies non-ectomesenchymal neural crest fates

Abstract: Waardenburg-Shah syndrome combines the reduced enteric nervous system characteristic of Hirschsprung's disease with reduced pigment cell number, although the cell biological basis of the disease is unclear. We have analysed a zebrafish Waardenburg-Shah syndrome model. We show that the colourless gene encodes a sox10 homologue, identify sox10 lesions in mutant alleles and rescue the mutant phenotype by ectopic sox10 expression. Using iontophoretic labelling of neural crest cells, we demonstrate that colourless mutant neural crest cells form ectomesenchymal fates. By contrast, neural crest cells which in wild types form non-ectomesenchymal fates generally fail to migrate and do not overtly differentiate. These cells die by apoptosis between 35 and 45 hours post fertilisation. We provide evidence that melanophore defects in colourless mutants can be largely explained by disruption of nacre/mitf expression. We propose that all defects of affected crest derivatives are consistent with a primary role for colourless/sox10 in specification of non-ectomesenchymal crest derivatives. This suggests a novel mechanism for the aetiology of Waardenburg-Shah syndrome in which affected neural crest derivatives fail to be generated from the neural crest.

The evolution of isochores.

Abstract: One of the most striking features of mammalian chromosomes is the variation in G+C content that occurs over scales of hundreds of kilobases to megabases, the so-called 'isochore' structure of the human genome. This variation in base composition affects both coding and non-coding sequences and seems to reflect a fundamental level of genome organization. However, although we have known about isochores for over 25 years, we still have a poor understanding of why they exist. In this article, we review the current evidence for the three main hypotheses.

The Action Turn: toward a transformational social science

Abstract: We offer an epistemological basis for action research, in order to increase the validity, the practical significance, and the transformational potential of social science. We start by outlining some of the paradigmatic issues which underlie action research, arguing for a “turn to action” which will complement the linguistic turn in the social sciences. Four key dimensions of an action science are discussed: the primacy of the practical, the centrality of participation, the requirement for experiential grounding, and the importance of normative, analogical theory. Three broad strategies for action research are suggested: first-person research/practice addresses the ability of a person to foster an inquiring approach to his or her own life; second-person research/practice engages a face-to-face group in collaborative inquiry; third-person research/practice asks how we can establish inquiring communities which reach beyond the immediate group to engage with whole organizations, communities and countries. The article argues that a transformational science needs to integrate first- second- and third-person voices in ways that increase the validity of the knowledge we use in our moment-to-moment living, that increase the effectiveness of our actions in real-time, and that remain open to unexpected transformation when our taken-for-granted assumptions, strategies, and habits are appropriately challenged. Illustrative references to studies that begin to speak to these questions are offered.

Crystal structure of the multifunctional paramyxovirus hemagglutinin-neuraminidase.

Abstract: Paramyxoviruses are the main cause of respiratory disease in children. One of two viral surface glycoproteins, the hemagglutinin-neuraminidase (HN), has several functions in addition to being the major surface antigen that induces neutralizing antibodies. Here we present the crystal structures of Newcastle disease virus HN alone and in complex with either an inhibitor or with the β-anomer of sialic acid. The inhibitor complex reveals a typical neuraminidase active site within a β-propeller fold. Comparison of the structures of the two complexes reveal differences in the active site, suggesting that the catalytic site is activated by a conformational switch. This site may provide both sialic acid binding and hydrolysis functions since there is no evidence for a second sialic acid binding site in HN. Evidence for a single site with dual functions is examined and supported by mutagenesis studies. The structure provides the basis for the structure-based design of inhibitors for a range of paramyxovirus-induced diseases.

Recombination and the population structures of bacterial pathogens

Abstract: The population structures of bacterial species are complex and often controversial. To a large extent, this is due to uncertainty about the frequency and impact of recombination in bacteria. The existence of clones within bacterial populations, and of linkage disequilibrium between alleles at different loci, is often cited as evidence for low rates of recombination. However, clones and linkage disequilibrium are almost inevitable in species that divide by binary fission and can be present in populations where recombination is frequent. In recent years, it has become possible to directly compare rates of recombination in different species. These studies indicate that in many bacterial species, including Neisseria meningitidis, Streptococcus pneumoniae, and Staphylococcus aureus, evolutionary change at neutral (housekeeping) loci is more likely to occur by recombination than mutation and can result in the elimination of any deep-rooted phylogenetic signal. In such species, the long-term evolution of the population is dominated by recombination, but this does not occur at a sufficiently high frequency to prevent the emergence of adaptive clones, although these are relatively short-lived and rapidly diversify.

First solvation shell of the Cu(II) aqua ion: evidence for fivefold coordination.

Abstract: We determined the structure of the hydrated Cu(II) complex by both neutron diffraction and first-principles molecular dynamics. In contrast with the generally accepted picture, which assumes an octahedrally solvated Cu(II) ion, our experimental and theoretical results favor fivefold coordination. The simulation reveals that the solvated complex undergoes frequent transformations between square pyramidal and trigonal bipyramidal configurations. We argue that this picture is also consistent with experimental data obtained previously by visible near-infrared absorption, x-ray absorption near-edge structure, and nuclear magnetic resonance methods. The preference of the Cu(II) ion for fivefold instead of sixfold coordination, which occurs for other cations of comparable charge and size, results from a Jahn-Teller destabilization of the octahedral complex.

SMEs: aligning IS and the strategic context

Abstract: Based on multiple-case research, this paper develops a model of strategic information systems (IS) investment in small and medium-sized enterprises (SMEs). IS investment is modelled as a function of an SME's strategic context as defined by its strategic focus, i.e. cost reduction versus value added and its market positioning, i.e. few versus many customers. The paper first investigates the ways in which IS may add value to organizations. It then outlines the use of IS in SMEs. This is followed by an analysis of competitiveness in small businesses. The paper develops an analytical model, which is termed the focus-dominance model, analyses case studies of 27 firms and reports that IS investment is strongly influenced by an SME's strategic context. Four cases are presented in order to illustrate the four different IS profiles identified. Finally, the implications for theory and practice are discussed.

A Taxonomy of Supply Networks

Abstract: SUMMARY There has been limited research into how different types of supply networks can be created and operated. This article develops a taxonomy of supply networks with a particular focus on managing network creation and operation. The taxonomy is based on a review of network literature from various academic perspectives and extensive empirical data across a variety of industry sectors including automotive, fast-moving consumer goods, electronics, pharmaceuticals, and communications technologies. The main differentiating factors for classifying a matrix of four types of supply network are found to be the degree of supply network dynamics and the degree of focal company supply network influence. Network characteristics and different patterns ofnetworking activities are identified for each type of supply network.

White-light supercontinuum generation with 60-ps pump pulses in a photonic crystal fiber

Abstract: The generation of a spatially single-mode white-light supercontinuum has been observed in a photonic crystal fiber pumped with 60-ps pulses of subkilowatt peak power. The spectral broadening is identified as being due to the combined action of stimulated Raman scattering and parametric four-wave-mixing generation, with a negligible contribution from the self-phase modulation of the pump pulses. The experimental results are in good agreement with detailed numerical simulations. These findings demonstrate that ultrafast femtosecond pulses are not needed for efficient supercontinuum generation in photonic crystal fibers.

DDT resistance in Drosophila correlates with Cyp6g1 over-expression and confers cross-resistance to the neonicotinoid imidacloprid

Abstract: Mutagenesis can be used as a means of predicting likely mechanisms of resistance to novel classes of insecticides. We used chemical mutagenesis in Drosophila to screen for mutants that had become resistant to imidacloprid, a neonicotinoid insecticide. Here we report the isolation of two new dominant imidacloprid-resistant mutants. By recombinational mapping we show that these map to the same location as Rst(2)DDT. Furthermore, we show that pre-existing Rst(2)DDT alleles in turn confer cross-resistance to imidacloprid. In order to localize the Rst(2)DDT gene more precisely, we mapped resistance to both DDT and imidacloprid with respect to P-element markers whose genomic location is known. By screening for recombinants between these P-elements and resistance we localized the gene between 48D5–6 and 48F3–6 on the polytene chromosome map. The genomic sequence in this interval shows a cluster of cytochrome P450 genes, one of which, Cyp6g1, is over-expressed in all resistant strains examined. We are now testing the hypothesis that resistance to both compounds is associated with over-expression of this P450 gene.

The Business Marketing Course: Managing in Complex Networks

Abstract: The new edition of this widely used business marketing text has been completely revised and rewritten. The Business Marketing Course provides a comprehensive insight into business marketing in a compact and accessible format that provides the ideal foundation for courses on business or industrial marketing. The new edition concentrates on the reality facing business marketers operating in complex and dynamic business networks. The book provides a structured approach to both technology and the development of the marketer’s offerings as well as an expanded guide on how to analyse business networks and customers and how to develop marketing strategy. The book is essential reading for students who are studying business markets. It is also an excellent guide for all managers who would like a clearer understanding of the complexity networks in which they operate.

Exergy analysis of the United Kingdom energy system

Abstract: The exergy method has been used to analyse changes in the structure of the UK energy system over a period of more than 30 years from 1965. A sectoral approach was employed, with the supply side examined in terms of themain energy sources, while final demand was separated into four energy end-use groups: the domestic, service, industrial and transport sectors. Estimates of sector-weighted or ‘lumped’ parameters, such as exergy efficiencies, were obtained from the particular characteristics of each sector. These were employed to determine the exergetic ‘improvement potential’ for critical elements of the energy system. Electricity generation together with final energy demand in the domestic sector and in transport are shown to account for nearly 80 per cent of the Second Law improvement potential. This poor thermodynamic performance is principally due to exergy losses in combustion and heat transfer processes associated with power generation, space heating and main transport modes. The results of th...

Spatio-temporal pattern formation on spherical surfaces: numerical simulation and application to solid tumour growth

Abstract: In this paper we examine spatio-temporal pattern formation in reaction-diffusion systems on the surface of the unit sphere in 3D. We first generalise the usual linear stability analysis for a two-chemical system to this geometrical context. Noting the limitations of this approach (in terms of rigorous prediction of spatially heterogeneous steady-states) leads us to develop, as an alternative, a novel numerical method which can be applied to systems of any dimension with any reaction kinetics. This numerical method is based on the method of lines with spherical harmonics and uses fast Fourier transforms to expedite the computation of the reaction kinetics. Numerical experiments show that this method efficiently computes the evolution of spatial patterns and yields numerical results which coincide with those predicted by linear stability analysis when the latter is known. Using these tools, we then investigate the role that pre-pattern (Turing) theory may play in the growth and development of solid tumours. The theoretical steady-state distributions of two chemicals (one a growth activating factor, the other a growth inhibitory factor) are compared with the experimentally and clinically observed spatial heterogeneity of cancer cells in small, solid spherical tumours such as multicell spheroids and carcinomas. Moreover, we suggest a number of chemicals which are known to be produced by tumour cells (autocrine growth factors), and are also known to interact with one another, as possible growth promoting and growth inhibiting factors respectively. In order to connect more concretely the numerical method to this application, we compute spatially heterogeneous patterns on the surface of a growing spherical tumour, modelled as a moving-boundary problem. The numerical results strongly support the theoretical expectations in this case. Finally in an appendix we give a brief analysis of the numerical method.

Individual and collective decision-making during nest site selection by the ant Leptothorax albipennis

Abstract: Social insect colonies possess remarkable abilities to select the best among several courses of action. In populous societies with highly efficient recruitment behaviour, decision-making is distributed across many individuals, each acting on limited local information with appropriate decision rules. To investigate the degree to which small societies with less efficient recruitment can also employ distributed decision-making, we studied nest site selection in Leptothorax albipennis. Colonies were found to make sophisticated choices, taking into account not only the intrinsic qualities of each site, but also its value relative to the available options. In choices between two sites, individual ants were able to visit both sites, compare them and choose the better one. However, most ants encountered only one site in the course of an emigration. These poorly informed ants also contributed to the colony's decision, because their probability of initiating recruitment to a site depended on its quality. This led to shorter latencies between discovery and recruitment to a superior site, and so created greater amplification via positive feedback of the population at the better site. In short, these small colonies make use of a distributed mechanism of information processing, but also take advantage of direct decision-making by well-informed individuals. The latter feature may in part stem from the limitations of their social structure, but may also reflect the stringent demand for unanimous decisions by house-hunting colonies of any size.

Role of psychology in pain management

Abstract: Psychological factors are central to the experience of pain, the delivery of effective analgesia and for the specific treatment of chronic pain and disability. Improvement in pain management can often be brought about by very simple, if subtle, changes in clinical practice. Although simple, these changes can have significant effects in the experience of pain, distress and use of health-care resources. For the chronic pain patient, the presentation is much more complex and the treatment interdisciplinary and programmatic. The evidence for the effectiveness of cognitive behaviour therapy for adults with chronic pain is now well established. This treatment should be available as a core part of any chronic pain service.

A Novel Approach to the Classification of the Transient Phenomena in Power Transformers Using Combined Wavelet Transform and Neural Network

Abstract: The wavelet transform is a powerful tool in the analysis of the power transformer transient phenomena because of its ability to extract information from the transient signals simultaneously in both the time and frequency domain. This paper presents a novel technique for accurate discrimination between an internal fault and a magnetizing inrush current in the power transformer by combining wavelet transforms with neural networks. The wavelet transform is firstly applied to decompose the differential current signals of the power transformer into a series of detailed wavelet components. The spectral energies of the wavelet components are calculated and then employed to train a neural network to discriminate an internal fault from the magnetizing inrush current. The simulated results presented clearly show that the proposed technique can accurately discriminate between an internal fault and a magnetizing inrush current in power transformer protection.

Transparency in Supply Relationships: Concept and Practice

Abstract: SUMMARY The problems associated with transparency in supply relationships — the two-way exchange of information and knowledge between customer and supplier — represent chronic difficulty for managers. The sensitivity of such exchanges appears to interfere with — even to negate — their effectiveness and value. This may be because of insufficient consideration of types of transparency and a propensity for customer domination in the relationship. This research is aimed at exploring these difficulties in order to understand the dynamics and varying nature of transparency in this context (including a proposed state of value transparency) and to suggest ways in which it might be approached in practice. In addition to the social and technology-led drivers identified for transparency, the research approach to the concept in supply has been driven by the observation that many of the traditional routines and activities occurring between industrial or commercial purchasers and their suppliers can be unnecessary and wasteful. This article presents the background to this hypothesis and records the development of a framework for discussion of the concept.

High concentrations of dexamethasone suppress the proliferation but not the differentiation or further maturation of human osteoblast precursors in vitro: relevance to glucocorticoid‐induced osteoporosis

Abstract: Objective The use of glucocorticoids (GCs) in the treatment of RA is a frequent cause of bone loss. In vitro, however, this same class of steroids has been shown to promote the recruitment and/or maturation of primitive osteogenic precursors present in the colony forming unit-fibroblastic (CFU-F) fraction of human bone and marrow. In an effort to reconcile these conflicting observations, we investigated the effects of the synthetic GC dexamethasone (Dx) on parameters of growth and osteogenic differentiation in cultures of bone marrow stromal cells derived from a large cohort of adult human donors (n=30). Methods Marrow suspensions were cultured in the absence and presence of Dx at concentrations between 10 pm and 1 microm. After 28 days we determined the number and diameter of colonies formed, the total number of cells, the surface expression of receptors for selected growth factors and extracellular matrix proteins and, based on the expression of the developmental markers alkaline phosphatase (AP) and the antigen recognized by the STRO-1 monoclonal antibody, the proportion of cells undergoing osteogenic differentiation and their extent of maturation. Results At a physiologically equivalent concentration, Dx had no effect on the adhesion of CFU-F or on their subsequent proliferation, but did promote their osteogenic differentiation and further maturation. These effects were independent of changes in the expression of the receptors for fibroblast growth factors, insulin-like growth factor 1, nerve growth factor, platelet-derived growth factors and parathyroid hormone/parathyroid hormone-related protein, but were associated with changes in the number of cells expressing the alpha(2) and alpha(4), but not beta(1), integrin subunits. At supraphysiological concentrations, the effects of Dx on the osteogenic recruitment and maturation of CFU-F and their progeny were maintained but at the expense of a decrease in cell number. Conclusions A decrease in the proliferation of osteogenic precursors, but not in their differentiation or maturation, is likely to be a key factor in the genesis of GC-induced bone loss.

Structure of Golgi α-mannosidase II: A target for inhibition of growth and metastasis of cancer cells

Abstract: Golgi α‐mannosidase II, a key enzyme in N ‐glycan processing, is a target in the development of anti‐ cancer therapies. The crystal structure of Drosophila Golgi α‐mannosidase II in the absence and presence of the anti‐cancer agent swainsonine and the inhibitor deoxymannojirimycin reveals a novel protein fold with an active site zinc intricately involved both in the substrate specificity of the enzyme and directly in the catalytic mechanism. Identification of a putative GlcNAc binding pocket in the vicinity of the active site cavity provides a model for the binding of the GlcNAcMan 5 GlcNAc 2 substrate and the consecutive hydrolysis of the α1,6‐ and α1,3‐linked mannose residues. The enzyme–inhibitor interactions observed provide insight into the catalytic mechanism, opening the door to the design of novel inhibitors of α‐mannosidase II.

Enhancing Strategy Evaluation in Scenario Planning: a Role for Decision Analysis

Abstract: Scenario planning can be a useful and attractive tool in strategic management. In a rapidly changing environment it can avoid the pitfalls of more traditional methods. Moreover, it provides a means of addressing uncertainty without recourse to the use of subjective probabilities, which can suffer from serious cognitive biases. However, one underdeveloped element of scenario planning is the evaluation of alternative strategies across the range of scenarios. If this is carried out informally then inferior strategies may be selected, while those formal evaluation procedures that have been suggested in relation to scenario planning are unlikely to be practical in most contexts. This paper demonstrates how decision analysis can be used to structure the strategy evaluation process in a way which avoids the problems associated with earlier proposals. The method is flexible, versatile and transparent and leads to a clear and documented rationale for the selection of a particular strategy.