Showing papers by "University of Birmingham published in 2000"

Learning from Abroad: The Role of Policy Transfer in Contemporary Policy‐Making

Abstract: In recent years there has been a growing body of literature within political science and international studies that directly and indirectly uses, discusses and analyzes the processes involved in lesson-drawing, policy convergence, policy diffusion and policy transfer. While the terminology and focus often vary, all of these studies are concerned with a similar process in which knowledge about policies, administrative arrangements, institutions and ideas in one political setting (past or present) is used in the development of policies, administrative arrangements, institutions and ideas in another political setting. Given that this is a growing phenomenon, it is something that anyone studying public policy needs to consider. As such, this article is divided into four major sections. The first section briefly considers the extent of, and reasons for, the growth of policy transfer. The second section then outlines a framework for the analysis of transfer. From here a third section presents a continuum for distinguishing between different types of policy transfer. Finally, the last section addresses the relationship between policy transfer and policy “failure.”

The genome sequence of the food-borne pathogen Campylobacter jejuni reveals hypervariable sequences

Abstract: Campylobacter jejuni, from the delta-epsilon group of proteobacteria, is a microaerophilic, Gram-negative, flagellate, spiral bacterium—properties it shares with the related gastric pathogen Helicobacter pylori. It is the leading cause of bacterial food-borne diarrhoeal disease throughout the world1. In addition, infection with C. jejuni is the most frequent antecedent to a form of neuromuscular paralysis known as Guillain–Barre syndrome2. Here we report the genome sequence of C. jejuni NCTC11168. C. jejuni has a circular chromosome of 1,641,481 base pairs (30.6% G+C) which is predicted to encode 1,654 proteins and 54 stable RNA species. The genome is unusual in that there are virtually no insertion sequences or phage-associated sequences and very few repeat sequences. One of the most striking findings in the genome was the presence of hypervariable sequences. These short homopolymeric runs of nucleotides were commonly found in genes encoding the biosynthesis or modification of surface structures, or in closely linked genes of unknown function. The apparently high rate of variation of these homopolymeric tracts may be important in the survival strategy of C. jejuni.

Stochastic ranking for constrained evolutionary optimization

Abstract: Penalty functions are often used in constrained optimization. However, it is very difficult to strike the right balance between objective and penalty functions. This paper introduces a novel approach to balance objective and penalty functions stochastically, i.e., stochastic ranking, and presents a new view on penalty function methods in terms of the dominance of penalty and objective functions. Some of the pitfalls of naive penalty methods are discussed in these terms. The new ranking method is tested using a (/spl mu/, /spl lambda/) evolution strategy on 13 benchmark problems. Our results show that suitable ranking alone (i.e., selection), without the introduction of complicated and specialized variation operators, is capable of improving the search performance significantly.

Histone acetylation and an epigenetic code

Abstract: The enzyme-catalyzed acetylation of the N-terminal tail domains of core histones provides a rich potential source of epigenetic information. This may be used both to mediate transient changes in transcription, through modification of promoter-proximal nucleosomes, and for the longer-term maintenance and modulation of patterns of gene expression. The latter may be achieved by setting specific patterns of histone acetylation, perhaps involving acetylation of particular lysine residues, across relatively large chromatin domains. The histone acetylating and deacetylating enzymes (HATs and HDACs, respectively) can be targeted to specific regions of the genome and show varying degrees of substrate specificity, properties that are consistent with a role in maintaining a dynamic, acetylation-based epigenetic code. The code may be read (ie. exert a functional effect) either through non-histone proteins that bind in an acetylation-dependent manner, or through direct effects on chromatin structure. Recent evidence raises the interesting possibility that an acetylation-based code may operate through both mitosis and meiosis, providing a possible mechanism for germ-line transmission of epigenetic changes.

The design of personal mobile technologies for lifelong learning

Abstract: This paper sets out a framework for the design of a new genre of educational technology — personal (handheld or wearable) computer systems that support learning from any location throughout a lifetime. We set out a theory of lifelong learning mediated by technology and indicate how it can provide requirements for the software, hardware, communications and interface design of a handheld learning resource, or HandLeR. The paper concludes with a description and formative evaluation of a demonstrator system for children aged 7–11.

Cartesian Genetic Programming

Abstract: This paper presents a new form of Genetic Programming called Cartesian Genetic Programming in which a program is represented as an indexed graph. The graph is encoded in the form of a linear string of integers. The inputs or terminal set and node outputs are numbered sequentially. The node functions are also separately numbered. The genotype is just a list of node connections and functions. The genotype is then mapped to an indexed graph that can be executed as a program. Evolutionary algorithms are used to evolve the genotype in a symbolic regression problem (sixth order polynomial) and the Santa Fe Ant Trail. The computational effort is calculated for both cases. It is suggested that hit effort is a more reliable measure of computational efficiency. A neutral search strategy that allows the fittest genotype to be replaced by another equally fit genotype (a neutral genotype) is examined and compared with non-neutral search for the Santa Fe ant problem. The neutral search proves to be much more effective.

Spin-orbit matrix elements for internally contracted multireference configuration interaction wavefunctions

Abstract: An efficient method for the calculation of Breit-Pauli spin-orbit matrix elements for internally contracted multireference configuration interaction wavefunctions is presented. Instead of taking all two-electron contributions of the wavefunction explicitly into account, the most important two-electron contributions of the spin-orbit operator are incorporated by means of an effective one-electron Fock operator. As a further refinement, explicit two-electron contributions can be reinstated for the dominant all-internal parts of the wavefunctions.

Metal nanoparticles and their assemblies

Abstract: Metal nanoparticles of varying sizes can be prepared by physical as well as chemical methods. They exhibit many fascinating properties, the size-dependent metal to nonmetal transition being an important one. Metal nanoparticles capped by thiols can be organized into ordered one-, two- and three-dimensional structures and these structures have potential applications in nanodevices. In this context, organization of arrays of metal nanoparticles with a fixed number of atoms assumes significance.

LMNA, encoding lamin A/C, is mutated in partial lipodystrophy.

Abstract: The lipodystrophies are a group of disorders characterized by the absence or reduction of subcutaneous adipose tissue. Partial lipodystrophy (PLD; MIM 151660) is an inherited condition in which a regional (trunk and limbs) loss of fat occurs during the peri-pubertal phase. Additionally, variable degrees of resistance to insulin action, together with a hyperlipidaemic state, may occur and simulate the metabolic features commonly associated with predisposition to atherosclerotic disease. The PLD locus has been mapped to chromosome 1q with no evidence of genetic heterogeneity. We, and others, have refined the location to a 5.3-cM interval between markers D1S305 and D1S1600 (refs 5, 6). Through a positional cloning approach we have identified five different missense mutations in LMNA among ten kindreds and three individuals with PLD. The protein product of LMNA is lamin A/C, which is a component of the nuclear envelope. Heterozygous mutations in LMNA have recently been identified in kindreds with the variant form of muscular dystrophy (MD) known as autosomal dominant Emery-Dreifuss MD (EDMD-AD; ref. 7) and dilated cardiomyopathy and conduction-system disease (CMD1A). As LMNA is ubiquitously expressed, the finding of site-specific amino acid substitutions in PLD, EDMD-AD and CMD1A reveals distinct functional domains of the lamin A/C protein required for the maintenance and integrity of different cell types.

Study of the Sorption of Divalent Metal Ions on to Peat

Abstract: A pseudo-second order rate equation describing the kinetics of sorption of divalent metal ions on to sphagnum moss peat at various initial metal ion concentrations and peat doses has been developed. The sorption kinetics were followed based on the concentrations of metal sorbed at various time intervals. Results show that chemical sorption processes might be rate-limiting for the sorption of divalent metal ions on to peat during agitated batch contact time experiments. The rate constant, the equilibrium sorption capacity and the initial sorption rate were calculated. From these parameters, an empirical model for predicting the concentrations of metal ions sorbed was derived.

Introduction to Action Research: Social Research for Social Change

Abstract: Introduction to Action Research: Social Research for Social Change. Davydd J. Greenwood and Morten Levin. Thousand Oaks, CA; Sage. 1998. 274 pp.

Examination of the psychometric properties of the Perceived Motivational Climate in Sport Questionnaire - 2 in a sample of female athletes

Abstract: We undertook two studies to determine the validity and reliability of the revised Perceived Motivational Climate in Sport Questionnaire (PMCSQ-2). In Study 1, 201 female athletes (mean age 16.4 years) were administered the initial version of the PMCSQ-2 and a measure of reported tension and pressure experienced in sport. Exploratory principal component analysis suggested that the PMCSQ-2 contained two higher-order scales (Task-Involving and Ego-Involving climates), each with three subscales (Task: Cooperative Learning, Effort/Improvement, Important Role; Ego: Intra-Team Member Rivalry, Unequal Recognition, Punishment for Mistakes). In Study 2, 385 female volleyball players (mean age 15.2 years) completed the PMCSQ-2, the Intrinsic Motivation Inventory and a measure of Team Satisfaction. Confirmatory factor analysis was applied to six competing models. The oblique six-factor model and oblique hierarchical model provided comparable fit to the data. Acceptable fit was reached based on model respecification. ...

Understanding Policy Networks: Towards a Dialectical Approach

Abstract: This article has two aims. First, we develop a dialectical model of the role that policy networks play in any explanation of policy outcomes. Our model is based upon a critique of existing approaches and emphasizes that the relationship between networks and outcomes is not a simple, unidimensional one. Rather, we argue that there are three interactive or dialectical relationships involved between: the structure of the network and the agents operating within them; the network and the context within which it operates; and the network and the policy outcome. Second, we use this model to help analyse and understand continuity and change in British agricultural policy since the 1930s. Obviously, one case is not sufficient to establish the utility of the model, but the case does illustrate both that policy networks can, and do, affect policy outcomes and that, in order to understand how that happens, we need to appreciate the role played by the three dialectical relationships highlighted in our model.

Do consumers really care about corporate responsibility? Highlighting the attitude—behaviour gap

Abstract: According to the press at the turn of the year 1999—2000, a good corporate reputation for responsible marketing is a key element in business success. One justification for this is the assumption that consumers are interested in how companies behave and this has an influence upon their consumption behaviour. There is also the suggestion that a financial pay‐off is to be gained from good behaviour. Conflicting reports in previous research cast doubt upon the reliability of these assumptions, and there are few studies which unequivocally support positive consumer purchasing in return for responsible marketing. This paper reviews current opinion and evidence in relation to the growing interest in corporate reputation, and reports findings from focus group research which casts doubt upon the efficacy of corporate reputation in influencing positive consumer purchase behaviour.

ABC of colorectal cancer: Epidemiology.

Abstract: In countries with a westernised lifestyle about half of all deaths are caused by circulatory disease and a quarter by cancer. Cancer is an important problem in both public health and political terms worldwide, irrespective of a country’s development. The most recent estimates of the global cancer burden suggest that there were 8.1 million new cases, excluding non-melanoma skin cancer, worldwide in 1990. About 10 million new cases are now diagnosed each year. Colorectal cancer is the fourth commonest form of cancer occurring worldwide, with an estimated 783 000 new cases diagnosed in 1990, the most recent year for which international estimates are available. It affects men and women almost equally, with about 401 000 new cases in men annually and 381 000 in women. The number of new cases of colorectal cancer worldwide has been increasing rapidly since 1975 (when it was 500 000). Worldwide, colorectal cancer represents 9.4% of all incident cancer in men and 10.1% in women. Colorectal cancer, however, is not equally common throughout the world. If the westernised countries (North America; those in northern, southern, and western Europe; Australasia; and New Zealand) are combined, colorectal cancer represents 12.6% of all incident cancer in westernised countries in men and 14.1% in women. Elsewhere colorectal cancer represents 7.7% and 7.9% of all incident cases in men and women respectively. Large differences exist in survival, according to the stage of disease. It is estimated that 394 000 deaths from colorectal cancer still occur worldwide annually, and colorectal cancer is the second commonest cause of death from any cancer in men in the European Union. Substantial differences in cancer survival seem to exist between Great Britain, Europe as a whole, and the United States. This variation in survival is not easily explained but could be related to stage of disease at presentation or treatment delivery, or both of these. The numbers of new cases of colorectal cancer worldwide has increased rapidly since 1975

A common polymorphism acts as an intragenic modifier of mutant p53 behaviour

Abstract: The p73 protein, a homologue of the tumour-suppressor protein p53, can activate p53-responsive promoters and induce apoptosis in p53-deficient cells. Here we report that some tumour-derived p53 mutants can bind to and inactivate p73. The binding of such mutants is influenced by whether TP53 (encoding p53) codon 72, by virtue of a common polymorphism in the human population, encodes Arg or Pro. The ability of mutant p53 to bind p73, neutralize p73-induced apoptosis and transform cells in cooperation with EJ-Ras was enhanced when codon 72 encoded Arg. We found that the Arg-containing allele was preferentially mutated and retained in squamous cell tumours arising in Arg/Pro germline heterozygotes. Thus, inactivation of p53 family members may contribute to the biological properties of a subset of p53 mutants, and a polymorphic residue within p53 affects mutant behaviour.

Capillary Bridges between Two Spherical Bodies

Abstract: A method was developed for measuring the capillary forces arising from microscopic pendular liquid bridges. Results are described for perfectly wetting bridges between spheres of equal and unequal radii. A comparison with the theoretical values calculated from a numerical integration of the Laplace−Young equation demonstrated the accuracy of the method. It also showed that existing criteria for gravitational distortion are too restrictive and that the influence of the disjoining pressure is negligible. The Derjaguin approximation for spheres of unequal size was shown to be relatively accurate for small bridge volumes and for separation distances excluding those at close-contact and near-rupture, which correspond to maxima in the filling angle. Closed-form approximations were developed in order to conveniently calculate the capillary forces between equal and unequal spheres as a function of the separation distance and for a given bridge volume and contact angle. A closed-form approximation was also develop...

Chandra Observation of Abell 2142: Survival of Dense Subcluster Cores in a Merger

Abstract: We use Chandra data to map the gas temperature in the central region of the merging cluster A2142. The cluster is markedly nonisothermal; it appears that the central cooling flow has been disturbed but not destroyed by a merger. The X-ray image exhibits two sharp, bow-shaped, shocklike surface brightness edges or gas density discontinuities. However, temperature and pressure profiles across these edges indicate that these are not shock fronts. The pressure is reasonably continuous across these edges, while the entropy jumps in the opposite sense to that in a shock (i.e., the denser side of the edge has lower temperature, and hence lower entropy). Most plausibly, these edges delineate the dense subcluster cores that have survived a merger and ram pressure stripping by the surrounding shock-heated gas.

Starburst-driven galactic winds — I. Energetics and intrinsic X-ray emission

Abstract: Starburst-driven galactic winds are responsible for the transport of mass, in particular metal-enriched gas, and energy out of galaxies and into the intergalactic medium. These outflows directly affect the chemical evolution of galaxies, and heat and enrich the intergalactic and intercluster medium. Currently, several basic problems preclude quantitative measurements of the impact of galactic winds: the unknown filling factors of, in particular, the soft X-ray-emitting gas prevent accurate measurements of densities, masses and energy content; multiphase temperature distributions of unknown complexity bias X-ray-determined abundances; unknown amounts of energy and mass may reside in hard to observe T∼105 K and T∼107.5 K phases; and the relative balance of thermal versus kinetic energy in galactic winds is not known. In an effort to address these problems, we perform an extensive hydrodynamical parameter study of starburst-driven galactic winds, motivated by the latest observation data on the best-studied starburst galaxy M82. We study how the wind dynamics, morphology and X-ray emission depend on the ISM distribution of the host galaxy, the starburst star formation history and strength, and the presence and distribution of mass-loading by dense clouds. We also investigate and discuss the influence of finite numerical resolution on the results of these simulations. We find that the soft X-ray emission from galactic winds comes from low filling factor (η≲2 per cent) gas, which contains only a small fraction (≲10 per cent) of the mass and energy of the wind, irrespective of whether the wind models are strongly mass-loaded or not. X-ray observations of galactic winds do not directly probe the gas that contains the majority of the energy, mass or metal-enriched gas in the outflow. X-ray emission comes from a complex phase-continuum of gas, covering a wide range of different temperatures and densities. No distinct phases, as are commonly assumed when fitting X-ray spectra, are seen in our models. Estimates of the properties of the hot gas in starburst galaxies based on fitting simple spectral models to existing X-ray spectra should be treated with extreme suspicion. The majority of the thermal and kinetic energy of these winds is in a volume-filling hot, T∼107 K, component which is extremely difficult to probe observationally because of its low density and hence low emissivity. Most of the total energy is in the kinetic energy of this hot gas, a factor that must be taken into account when attempting to constrain wind energetics observationally. We also find that galactic winds are efficient at transporting large amounts of energy out of the host galaxy, in contrast to their inefficiency at transporting mass out of star-forming galaxies.

Functional Heterogeneity and High Frequencies of Cytomegalovirus-Specific CD8+ T Lymphocytes in Healthy Seropositive Donors

Abstract: Human cytomegalovirus (HCMV) infection is largely asymptomatic in the immunocompetent host, but remains a major cause of morbidity in immunosuppressed individuals. Using the recently described technique of staining antigen-specific CD8 + T cells with peptide-HLA tetrameric complexes, we have demonstrated high levels of antigen-specific cells specific for HCMV peptides and show that this may exceed 4% of CD8 + T cells in immunocompetent donors. Moreover, by staining with tetramers in combination with antibodies to cell surface markers and intracellular cytokines, we demonstrate functional heterogeneity of HCMV-specific populations. A substantial proportion of these are effector cytotoxic T lymphocytes, as demonstrated by their ability to lyse peptide-pulsed targets in “fresh” killing assays. These data suggest that the immune response to HCMV is periodically boosted by a low level of HCMV replication and that sustained immunological surveillance contributes to the maintenance of host-pathogen homeostasis. These observations should improve our understanding of the immunobiology of persistent viral infection.

The Systemic Lupus International Collaborating Clinics/American College of Rheumatology (SLICC/ACR) Damage Index for Systemic Lupus Erythematosus International Comparison.

Abstract: Objective. To compare patients with systemic lupus erythematosus ISLE) from different centers with respect to demographics and Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SLICC/ACR Dl) scores, and to assess whether the SLICC/ACR DI changed over time, and whether initial DI scores were related to outcome. Methods. Members of SLICC completed DI scores and patient demographics on patients followed in their centers. Information was provided at 2, 5-10, and > 10 years of followup. Data were entered on computer and analyzed on SPSS/PC+ and SAS using descriptive statistics and analysis of variance. Results. Information for 1297 patients within 2 years of first clinic visit was submitted from 8 centers. There were 1187 women and 110 ten with a mean age at diagnosis of SLE of 32 years. Seven hundred sixty-two were Caucasian, 423 were black, and the remainder were of other races. There were more blacks in the American centers than in Canadian or European centers. Five centers provided information for the 3 time periods. The DI increased over time. Ninety-nine patients had died. Higher SLICC/ACR DI scores were documented in patients who went on to die. Conclusion. The SLICC/ACR DI is a valid measure for damage in SLE.