Showing papers by "University of Manchester published in 2004"

Electric Field Effect in Atomically Thin Carbon Films

Abstract: We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.

Politically Connected Firms

Abstract: Examination of firms in 47 countries shows a widespread overlap of controlling shareholders and top officers who are connected with national parliaments or governments, particularly in countries with higher levels of corruption, with barriers to foreign investment, and with more transparent systems. Connections are diminished when regulations set more limits on official behavior. Additionally, I show that the announcement of a new political connection results in a significant increase in value.

Sequence and comparative analysis of the chicken genome provide unique perspectives on vertebrate evolution

Abstract: We present here a draft genome sequence of the red jungle fowl, Gallus gallus. Because the chicken is a modern descendant of the dinosaurs and the first non-mammalian amniote to have its genome sequenced, the draft sequence of its genome--composed of approximately one billion base pairs of sequence and an estimated 20,000-23,000 genes--provides a new perspective on vertebrate genome evolution, while also improving the annotation of mammalian genomes. For example, the evolutionary distance between chicken and human provides high specificity in detecting functional elements, both non-coding and coding. Notably, many conserved non-coding sequences are far from genes and cannot be assigned to defined functional classes. In coding regions the evolutionary dynamics of protein domains and orthologous groups illustrate processes that distinguish the lineages leading to birds and mammals. The distinctive properties of avian microchromosomes, together with the inferred patterns of conserved synteny, provide additional insights into vertebrate chromosome architecture.

Essential guide to qualitative methods in organizational research

Abstract: Promoting New Research Practices in Organizational Research - Gillian Symon and Catherine Cassell Using Interviews in Qualitative Research - Nigel King Electronic Interviews in Organizational Research - Stephanie J Morgan and Gillian Symon Life Histories - Gill Musson Critical Incident Technique - Elizabeth Chell Repertory Grids - Catherine Cassell and Susan Walsh Cognitive Mapping in Organizational Research - Seonaidh McDonald, Kevin Daniels and Claire Harris The Twenty Statements Test - Anne Rees and Nigel Nicholson Qualitative Research Diaries - Gillian Symon Stories in Organizational Research - Yiannis Gabriel and Dorothy S Griffiths Pictorial Representation - David R Stiles Group Methods of Organizational Analysis - Chris Steyaert and Ren[ac]e Bouwen Participant Observation - David Waddington Analytic Induction - Phil Johnson Critical Research and Analysis in Organizations - Kate Mackenzie Davey and Andreas P D Liefooghe Hermeneutic Understanding - John McAuley Discourse Analysis - Penny Dick Talk-in-Interaction/Conversation Analysis - Dalvir Samra-Fredericks Attributional Coding - Jo Silvester Grounded Theory in Organizational Research - Hannakaisa L[um]ansisalmi, Jos[ac]e-Maria Peir[ac]o and Mika Kivim[um]aki Using Templates in the Thematic Analysis of Text - Nigel King Using Data Matrices - Sara Nadin and Catherine Cassell Preserving, Sharing and Reusing Data from Qualitative Research - Louise Corti, Paul Thompson and Janet Fink Methods and Strategies Historical Analysis of Company Documents - Michael Rowlinson Ethnography - John D Brewer Case Study Research - Jean Hartley Soft Systems Analysis - Susan Walsh and Chris Clegg Reflections and Update Action Research and Research Action - Frank Heller A Family of Methods Co-Research - John Bennington and Jean Hartley Insider/Outsider Teams for Organizational Research The Future Conference - Fran Ryan

Taverna: a tool for the composition and enactment of bioinformatics workflows

Abstract: Motivation:In silico experiments in bioinformatics involve the co-ordinated use of computational tools and information repositories. A growing number of these resources are being made available with programmatic access in the form of Web services. Bioinformatics scientists will need to orchestrate these Web services in workflows as part of their analyses. Results: The Taverna project has developed a tool for the composition and enactment of bioinformatics workflows for the life sciences community. The tool includes a workbench application which provides a graphical user interface for the composition of workflows. These workflows are written in a new language called the simple conceptual unified flow language (Scufl), where by each step within a workflow represents one atomic task. Two examples are used to illustrate the ease by which in silico experiments can be represented as Scufl workflows using the workbench application. Availability: The Taverna workflow system is available as open source and can be downloaded with example Scufl workflows from http://taverna.sourceforge.net

New Fluorescence Parameters for the Determination of QA Redox State and Excitation Energy Fluxes.

Abstract: A number of useful photosynthetic parameters are commonly derived from saturation pulse-induced fluorescence analysis. We show, that qP, an estimate of the fraction of open centers, is based on a pure ‘puddle’ antenna model, where each Photosystem (PS) II center possesses its own independent antenna system. This parameter is incompatible with more realistic models of the photosynthetic unit, where reaction centers are connected by shared antenna, that is, the so-called ‘lake’ or ‘connected units’ models. We thus introduce a new parameter, qL, based on a Stern–Volmer approach using a lake model, which estimates the fraction of open PS II centers. We suggest that qL should be a useful parameter for terrestrial plants consistent with a high connectivity of PS II units, whereas some marine species with distinct antenna architecture, may require the use of more complex parameters based on intermediate models of the photosynthetic unit. Another useful parameter calculated from fluorescence analysis is ΦII, the yield of PS II. In contrast to qL, we show that the ΦII parameter can be derived from either a pure ‘lake’ or pure ‘puddle’ model, and is thus likely to be a robust parameter. The energy absorbed by PS II is divided between the fraction used in photochemistry, ΦII, and that lost non-photochemically. We introduce two additional parameters that can be used to estimate the flux of excitation energy into competing non-photochemical pathways, the yield induced by downregulatory processes, ΦNPQ, and the yield for other energy losses, ΦNO.

Role of metal-reducing bacteria in arsenic release from Bengal delta sediments

Abstract: The contamination of ground waters, abstracted for drinking and irrigation, by sediment-derived arsenic threatens the health of tens of millions of people worldwide, most notably in Bangladesh and West Bengal1,2,3. Despite the calamitous effects on human health arising from the extensive use of arsenic-enriched ground waters in these regions, the mechanisms of arsenic release from sediments remain poorly characterized and are topics of intense international debate4,5,6,7,8. We use a microscosm-based approach to investigate these mechanisms: techniques of microbiology and molecular ecology are used in combination with aqueous and solid phase speciation analysis of arsenic. Here we show that anaerobic metal-reducing bacteria can play a key role in the mobilization of arsenic in sediments collected from a contaminated aquifer in West Bengal. We also show that, for the sediments in this study, arsenic release took place after Fe(iii) reduction, rather than occurring simultaneously. Identification of the critical factors controlling the biogeochemical cycling of arsenic is one important contribution to fully informing the development of effective strategies to manage these and other similar arsenic-rich ground waters worldwide.

Oscillations in NF-κB Signaling Control the Dynamics of Gene Expression

Abstract: Signaling by the transcription factor nuclear factor kappa B (NF-kappaB) involves its release from inhibitor kappa B (IkappaB) in the cytosol, followed by translocation into the nucleus. NF-kappaB regulation of IkappaBalpha transcription represents a delayed negative feedback loop that drives oscillations in NF-kappaB translocation. Single-cell time-lapse imaging and computational modeling of NF-kappaB (RelA) localization showed asynchronous oscillations following cell stimulation that decreased in frequency with increased IkappaBalpha transcription. Transcription of target genes depended on oscillation persistence, involving cycles of RelA phosphorylation and dephosphorylation. The functional consequences of NF-kappaB signaling may thus depend on number, period, and amplitude of oscillations.

Competition and Innovation: An Inverted U Relationship

Abstract: This paper investigates the relationship between product market competition and innovation. It uses the radical policy reforms in the UK as instruments for changes in product market competition, and finds a robust inverted-U relationship between competition and patenting. It then develops an endogenousm growth model with step-by-step innovation that can deliver this inverted-U pattern. In this model, competition has an ambiguous effect on innovation. On the one hand, it discourages laggard firms from innovating, as it reduces their rents from catching up with the leaders in the same industry. On the other hand, it encourages neck-and-neck firms to innovate in order to escape competition with their rival. The inverted-U pattern results from the interplay between these two effects, together with the effect of competition on the equilibrium industry structure. The model generates two additional predictions: on the relationship between competition and the average technological distance between leaders and followers across industries; and on the relationship between the distance of an industry to its technological frontier and the steepness of the inverted-U. Both predictions are supported by the data.

Rivastigmine for Dementia Associated with Parkinson's Disease

Abstract: background Cholinergic deficits are prominent in patients who have dementia associated with Parkinson’s disease. We investigated the effects of the dual cholinesterase inhibitor rivastigmine in such patients. methods Patients in whom mild-to-moderate dementia developed at least 2 years after they received a clinical diagnosis of Parkinson’s disease were randomly assigned to receive placebo or 3 to 12 mg of rivastigmine per day for 24 weeks. Primary efficacy variables were the scores for the cognitive subscale of the Alzheimer’s Disease Assessment Scale (ADAS-cog) and Alzheimer’s Disease Cooperative Study–Clinician’s Global Impression of Change (ADCS-CGIC). Secondary clinical outcomes were the scores for the Alzheimer’s Disease Cooperative Study–Activities of Daily Living, the 10-item Neuropsychiatric Inventory, the Mini–Mental State Examination, Cognitive Drug Research power of attention tests, the Verbal Fluency test, and the Ten Point Clock-Drawing test. results A total of 541 patients were enrolled, and 410 completed the study. The outcomes were better among patients treated with rivastigmine than among those who received placebo; however, the differences between these two groups were moderate and similar to those reported in trials of rivastigmine for Alzheimer’s disease. Rivastigmine-treated patients had a mean improvement of 2.1 points in the score for the 70-point ADAS-cog, from a baseline score of 23.8, as compared with a 0.7-point worsening in the placebo group, from a baseline score of 24.3 (P<0.001). Clinically meaningful improvements in the scores for the ADCS-CGIC were observed in 19.8 percent of patients in the rivastigmine group and 14.5 percent of those in the placebo group, and clinically meaningful worsening was observed in 13.0 percent and 23.1 percent, respectively (mean score at 24 weeks, 3.8 and 4.3, respectively; P=0.007). Significantly better outcomes were seen with rivastigmine with respect to all secondary efficacy variables. The most frequent adverse events were nausea (affecting 29.0 percent of patients in the rivastigmine group and 11.2 percent of those in the placebo group, P<0.001), vomiting (16.6 and 1.7 percent, P<0.001), and tremor (10.2 and 3.9 percent, P=0.01). conclusions In this placebo-controlled study, rivastigmine was associated with moderate improvements in dementia associated with Parkinson’s disease but also with higher rates of nausea, vomiting, and tremor.

‘Globalizing’ regional development: a global production networks perspective

Abstract: Recent literature concerning regional development has placed significant emphasis on local institutional structures and their capacity to ‘hold down’ the global. Conversely, work on inter-firm networks – such as the global commodity chain approach – has highlighted the significance of the organizational structures of global firms’ production systems and their relation to industrial upgrading. In this paper, drawing upon a global production networks perspective, we conceptualize the connections between ‘globalizing’ processes, as embodied in the production networks of transnational corporations, and regional development in specific territorial formations. We delimit the ‘strategic coupling’ of the global production networks of firms and regional economies which ultimately drives regional development through the processes of value creation, enhancement and capture. In doing so, we stress the multi-scalarity of the forces and processes underlying regional development, and thus do not privilege one particular geographical scale. By way of illustration, we introduce an example drawn from recent research into global production networks in East Asia and Europe. The example profiles the investments of car manufacturer BMW in Eastern Bavaria, Germany and Rayong, Thailand, and considers their implications for regional development.

Qualitative Research and Translation Dilemmas

Abstract: The focus of this article is an examination of translation dilemmas in qualitative research. Specifically it explores three questions: whether methodologically it matters if the act of translation ...

Globalisation, Economic Geography and the Strategy of Multinational Enterprises

Abstract: The intention of this paper is to review the literature linking ownership and location strategies to economic geography and theories of globalisation and to explore new areas of research. This paper examines globalisation in terms of conflicts between markets and economic management, and suggests that the differential pace of globalisation across markets presents a number of challenges to policy makers in local, national and regional governments, and in international institutions. In examining the changing location and ownership strategies of MNEs, it shows that the increasingly sophisticated decision making of managers in MNEs is slicing the activities of firms more finely and in finding optimum locations for each closely defined activity, they are deepening the international division of labour. Ownership strategies, too, are becoming increasingly complex, leading to a control matrix that runs from wholly owned units via FDI through market relationships such as subcontracting, including joint ventures as options on subsequent decisions in a dynamic pattern. The input of lessons from economic geography is thus becoming more important in understanding the key developments in international business. The consequences of the globalisation of production and consumption represent political challenges, and reaction against these changes has led to a questioning of the effects of global capitalism as well as to its moral basis. These four issues are closely intertwined and present a formidable research agenda to which the international business research community is uniquely fitted to respond.

Diabetic Somatic Neuropathies

Abstract: ropathic pain (7–10), and this and other putative mechanisms will be discussed The clinical features, diagnosis, and management of the focal and multifocal neuropathies will be described A major portion of this review will discuss the clinical features, assessment, and management of the patient with the most common form of DN, diabetic distal sensory polyneuropathy (DPN) The late sequelae of DPN and their prevention will also be described Finally, practical guidelines for the screening of DPN in clinical practice will be provided For further details on this topic, please refer to recent reviews (11– 18)

Structure and deterioration of semantic memory: a neuropsychological and computational investigation.

Abstract: Wernicke (1900, as cited in G. H. Eggert, 1977) suggested that semantic knowledge arises from the interaction of perceptual representations of objects and words. The authors present a parallel distributed processing implementation of this theory, in which semantic representations emerge from mechanisms that acquire the mappings between visual representations of objects and their verbal descriptions. To test the theory, they trained the model to associate names, verbal descriptions, and visual representations of objects. When its inputs and outputs are constructed to capture aspects of structure apparent in attribute-norming experiments, the model provides an intuitive account of semantic task performance. The authors then used the model to understand the structure of impaired performance in patients with selective and progressive impairments of conceptual knowledge. Data from 4 well-known semantic tasks revealed consistent patterns that find a ready explanation in the model. The relationship between the model and related theories of semantic representation is discussed.

A double-pulsar system: A rare laboratory for relativistic gravity and plasma physics

Abstract: The clocklike properties of pulsars moving in the gravitational fields of their unseen neutron-star companions have allowed unique tests of general relativity and provided evidence for gravitational radiation. We report here the detection of the 2.8-second pulsar J07373039B as the companion to the 23-millisecond pulsar J07373039A in a highly relativistic double neutron star system, allowing unprecedented tests of fundamental gravitational physics. We observed a short eclipse of J07373039A by J07373039B and orbital modulation of the flux density and the pulse shape of J07373039B, probably because of the influence of J07373039A’s energy flux on its magnetosphere. These effects will allow us to probe magneto-ionic properties of a pulsar magnetosphere. Double neutron star (DNS) binaries are rare, and only six such systems are known. How

Oxidation-responsive polymeric vesicles.

Abstract: Vesicles formed in water by synthetic macro-amphiphiles have attracted much attention as nanocontainers having properties that extend the physical and chemical limits of liposomes. We sought to develop ABA block copolymeric amphiphiles that self-assemble into unilamellar vesicles that can be further oxidatively destabilized. We selected poly(ethylene glycol) (PEG) as the hydrophilic A blocks, owing to its resistance to protein adsorption and low toxicity. As hydrophobic B blocks, we selected poly(propylene sulphide) (PPS), owing to its extreme hydrophobicity, its low glass-transition temperature, and most importantly its oxidative conversion from a hydrophobe to a hydrophile, poly(propylene sulphoxide) and ultimately poly(propylene sulphone). This is the first example of the use of oxidative conversions to destabilize such carriers. This new class of oxidation-responsive polymeric vesicles may find applications as nanocontainers in drug delivery, biosensing and biodetection.

A common open representation of mass spectrometry data and its application to proteomics research

Abstract: A broad range of mass spectrometers are used in mass spectrometry (MS)-based proteomics research. Each type of instrument possesses a unique design, data system and performance specifications, resulting in strengths and weaknesses for different types of experiments. Unfortunately, the native binary data formats produced by each type of mass spectrometer also differ and are usually proprietary. The diverse, nontransparent nature of the data structure complicates the integration of new instruments into preexisting infrastructure, impedes the analysis, exchange, comparison and publication of results from different experiments and laboratories, and prevents the bioinformatics community from accessing data sets required for software development. Here, we introduce the 'mzXML' format, an open, generic XML (extensible markup language) representation of MS data. We have also developed an accompanying suite of supporting programs. We expect that this format will facilitate data management, interpretation and dissemination in proteomics research.

Solution-Processed, Organophilic Membrane Derived from a Polymer of Intrinsic Microporosity

Abstract: A polymer with a rigid, randomly contorted molecular structure (see Figure), incorporating fused rings connected by spiro-centres, may be precipitated or cast from solution to give microporous powders and membranes stable up to temperatures of 350 °C, with apparent surface areas > 600 m2 g–1. Organophilic membranes may be formed, as demonstrated by the separation of phenol from water by pervaporation.

Globalisation, economic geography and the strategy of multinational enterprises

Abstract: The intention of this paper is to review the literature linking ownership and location strategies to economic geography and theories of globalisation and to explore new areas of research. This paper examines globalisation in terms of conflicts between markets and economic management, and suggests that the differential pace of globalisation across markets presents a number of challenges to policy makers in local, national and regional governments, and in international institutions. In examining the changing location and ownership strategies of MNEs, it shows that the increasingly sophisticated decision making of managers in MNEs is slicing the activities of firms more finely and in finding optimum locations for each closely defined activity, they are deepening the international division of labour. Ownership strategies, too, are becoming increasingly complex, leading to a control matrix that runs from wholly owned units via FDI through market relationships such as subcontracting, including joint ventures as options on subsequent decisions in a dynamic pattern. The input of lessons from economic geography is thus becoming more important in understanding the key developments in international business. The consequences of the globalisation of production and consumption represent political challenges, and reaction against these changes has led to a questioning of the effects of global capitalism as well as to its moral basis. These four issues are closely intertwined and present a formidable research agenda to which the international business research community is uniquely fitted to respond.

Generalized multilevel structural equation modeling

Abstract: A unifying framework for generalized multilevel structural equation modeling is introduced. The models in the framework, called generalized linear latent and mixed models (GLLAMM), combine features of generalized linear mixed models (GLMM) and structural equation models (SEM) and consist of a response model and a structural model for the latent variables. The response model generalizes GLMMs to incorporate factor structures in addition to random intercepts and coefficients. As in GLMMs, the data can have an arbitrary number of levels and can be highly unbalanced with different numbers of lower-level units in the higher-level units and missing data. A wide range of response processes can be modeled including ordered and unordered categorical responses, counts, and responses of mixed types. The structural model is similar to the structural part of a SEM except that it may include latent and observed variables varying at different levels. For example, unit-level latent variables (factors or random coefficients) can be regressed on cluster-level latent variables. Special cases of this framework are explored and data from the British Social Attitudes Survey are used for illustration. Maximum likelihood estimation and empirical Bayes latent score prediction within the GLLAMM framework can be performed using adaptive quadrature in gllamm, a freely available program running in Stata.

Understanding the factors that govern the deposition and morphology of thin films of ZnO from aqueous solution

Abstract: The influence of the choice of complexing ligand, zinc counter-ion, pH, ionic strength, supersaturation, deposition time and substrate on the nature of ZnO films grown from chemical baths (CBD) are discussed. There are significant differences between CBD and similar routes such as hydrothermal methods for ZnO films. Modelling of speciation and experimental results suggest that acicular ZnO morphologies are best obtained by limiting the concentration of one of either Zn2+ or OH− in the presence of a large excess of the other. The presence of a prior ZnO layer can facilitate nucleation at lower levels of supersaturation and enable size tailoring of ZnO columns. The point at which the substrate is introduced into the bath is crucial and can lead to a significant difference in both the width of the rods and optical transparency of the films. HR-TEM has yielded important structural information and a growth mechanism for single crystalline ZnO rods by CBD is described for the first time.

A meta-analysis of prior corticosteroid use and fracture risk.

Abstract: The relationship between use of corticosteroids and fracture risk was estimated in a meta-analysis of data from seven cohort studies of approximately 42,000 men and women. Current and past use of corticosteroids was an important predictor of fracture risk that was independent of prior fracture and BMD. INTRODUCTION: The aims of this study were to validate that corticosteroid use is a significant risk factor for fracture in an international setting and to explore the effects of age and sex on this risk. MATERIALS AND METHODS: We studied 42,500 men and women from seven prospectively studied cohorts followed for 176,000 patient-years. The cohorts comprised the EPOS/EVOS study, CaMos, the Rotterdam Study, Dubbo Osteoporosis Epidemiology Study (DOES), and prospective cohorts at Sheffield, Rochester, and Gothenburg. The effect of ever use of corticosteroids, BMD, age, and sex on all fracture, osteoporotic fracture, and hip fracture risk alone was examined using Poisson regression in each cohort and for each sex. The results of the different studies were merged from the weighted beta coefficients. RESULTS: Previous corticosteroid use was associated with a significantly increased risk of any fracture, osteoporotic fracture, and hip fracture when adjusted for BMD. Relative risk of any fracture ranged from 1.98 at the age of 50 years to 1.66 at the age of 85 years. For osteoporotic fracture, the range of relative risk was 2.63-1.71, and for hip fracture 4.42-2.48. The estimate of relative risk was higher at younger ages, but not significantly so. No significant difference in risk was seen between men and women. The risk was marginally and not significantly upwardly adjusted when BMD was excluded from the model. The risk was independent of prior fracture. In the three cohorts that documented current corticosteroid use, BMD was significantly reduced at the femoral neck, but fracture risk was still only partly explained by BMD. CONCLUSION: We conclude that prior and current exposure to corticosteroids confers an increased risk of fracture that is of substantial importance beyond that explained by the measurement of BMD. Its identification on an international basis validates the use of this risk factor in case-finding strategies.

Cognitive therapy for the prevention of psychosis in people at ultra-high risk: randomised controlled trial.

Abstract: Background Advances in the ability to identify people at high risk of developing psychosis have generated interest in the possibility of preventing psychosis. Aims To evaluate the efficacy of cognitive therapy for the prevention of transition to psychosis. Method A randomised controlled trial compared cognitive therapy with treatment as usual in 58 patients at ultra-high riskof developing a first episode of psychosis. Therapy was provided over 6 months, and all patients were monitored on a monthly basis for 12 months. Results Logistic regression demonstrated that cognitive therapy significantly reduced the likelihood of making progression to psychosis as defined on the Positive and Negative Syndrome Scale over 12 months. In addition, it significantly reduced the likelihood of being prescribed antipsychotic medication and of meeting criteria for a DSM–IV diagnosis of a psychotic disorder. Analysis of covariance showed that the intervention also significantly improved positive symptoms of psychosis in this population over the 12-month period Conclusions Cognitive therapy appears to be an acceptable and efficacious intervention for people at high risk of developing psychosis.

Linking physicians' pay to the quality of care--a major experiment in the United kingdom.

Abstract: In this Health Policy Report, the author describes a major pay-for-performance program that is being implemented in the United Kingdom. Additional government payments to family practitioners will be based on the quality of care they deliver. Family practitioners can earn up to 1050 quality bonus points (expected to be worth more than $75,000 in gross income) for performing well on a complex set of indicators that measure the quality of clinical care, organization of the practice, and experience of the patients.