721 research outputs found

    RAPD for the typing of coagulase-negative staphylococci implicated in catheter-related bloodstream infection

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    Objectives: A rapid random amplification of polymorphic DNA (RAPD) technique was developed to distinguish between strains of coagulase-negative staphylococci (CoNS) involved in central venous catheter (CVC)-related bloodstream infection. Its performance was compared with that of pulsed-field gel electrophoresis (PFGE). Methods: Patients at the University Hospital Birmingham NHS Foundation Trust, U.K. who underwent stem cell transplantation and were diagnosed with CVC-related bloodstream infection due to CoNS whilst on the bone marrow transplant unit were studied. Isolates of CoNS were genotyped by PFGE and RAPD, the latter employing a single primer and a simple DNA extraction method. Results: Both RAPD and PFGE were highly discriminatory (Simpson's diversity index, 0.96 and 0.99, respectively). Within the 49 isolates obtained from blood cultures of 33 patients, 20 distinct strains were identified by PFGE and 25 by RAPD. Of the 25 strains identified by RAPD, nine clusters of CoNS contained isolates from multiple patients, suggesting limited nosocomial spread. However, there was no significant association between time of inpatient stay and infection due to any particular strain. Conclusion: The RAPD technique presented allows CoNS strains to be genotyped with high discrimination within 4 h, facilitating real-time epidemiological investigations. In this study, no single strain of CoNS was associated with a significant number of CVC-related bloodstream infections. © 2005 Published by Elsevier Ltd on behalf of the British Infection Society

    Neutron scattering and molecular correlations in a supercooled liquid

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    We show that the intermediate scattering function Sn(q,t)S_n(q,t) for neutron scattering (ns) can be expanded naturely with respect to a set of molecular correlation functions that give a complete description of the translational and orientational two-point correlations in the liquid. The general properties of this expansion are discussed with special focus on the qq-dependence and hints for a (partial) determination of the molecular correlation functions from neutron scattering results are given. The resulting representation of the static structure factor Sn(q)S_n(q) is studied in detail for a model system using data from a molecular dynamics simulation of a supercooled liquid of rigid diatomic molecules. The comparison between the exact result for Sn(q)S_n(q) and different approximations that result from a truncation of the series representation demonstrates its good convergence for the given model system. On the other hand it shows explicitly that the coupling between translational (TDOF) and orientational degrees of freedom (ODOF) of each molecule and rotational motion of different molecules can not be neglected in the supercooled regime.Further we report the existence of a prepeak in the ns-static structure factor of the examined fragile glassformer, demonstrating that prepeaks can occur even in the most simple molecular liquids. Besides examining the dependence of the prepeak on the scattering length and the temperature we use the expansion of Sn(q)S_n(q) into molecular correlation functions to point out intermediate range orientational order as its principle origin.Comment: 13 pages, 7 figure

    Determinants of contractor satisfaction

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    Performance in the construction industry is increasingly scrutinized as a result of the delays, cost overruns and poor quality of the industry’s products and services. Increasingly, disputes, conflicts and mismatches of objectives among participants are contributory factors. Performance measurement approaches have been developed to overcome these problems. However, these approaches focus primarily on objective measures to the exclusion of subjective measures, particularly those concerning contractor satisfaction (Co-S). The contractor satisfaction model (CoSMo) developed here is intended to rectify the situation. Data derived from a questionnaire survey of 75 large contractors in Malaysia in respect of a key project are analysed to identify participant factors and their strength of relationship with Co-S dimensions. The results are presented in the form of eight regression equations. The outcome is a tool for use by project participants to provide a better understanding of how they, and the project, affect contractor satisfaction. The developed model sheds some light on a hitherto unknown aspect of construction management in providing an increased awareness of the importance of major Malaysian construction contractors’ needs in the execution of successful projects

    The Global Gridded Crop Model Intercomparison: Data and modeling protocols for Phase 1 (v1.0)

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    We present protocols and input data for Phase 1 of the Global Gridded Crop Model Intercomparison, a project of the Agricultural Model Intercomparison and Improvement Project (AgMIP). The project includes global simulations of yields, phenologies, and many land-surface fluxes using 12–15 modeling groups for many crops, climate forcing data sets, and scenarios over the historical period from 1948 to 2012. The primary outcomes of the project include (1) a detailed comparison of the major differences and similarities among global models commonly used for large-scale climate impact assessment, (2) an evaluation of model and ensemble hindcasting skill, (3) quantification of key uncertainties from climate input data, model choice, and other sources, and (4) a multi-model analysis of the agricultural impacts of large-scale climate extremes from the historical record

    Uncertainties in global crop model frameworks: effects of cultivar distribution, crop management and soil handling on crop yield estimates

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    Global gridded crop models (GGCMs) combine field-scale agronomic models or sets of plant growth algorithms with gridded spatial input data to estimate spatially explicit crop yields 40 and agricultural externalities at the global scale. Differences in GGCM outputs arise from the use of different bio-physical models, setups, and input data. While algorithms have been in the focus of recent GGCM comparisons, this study investigates differences in maize and wheat yield estimates from five GGCMs based on the public domain field-scale model Environmental Policy Integrated Climate (EPIC) that participate in the AgMIP Global Gridded Crop Model 45 Intercomparison (GGCMI) project. Albeit using the same crop model, the GGCMs differ in model version, input data, management assumptions, parameterization, geographic distribution of cultivars, and selection of subroutines e.g. for the estimation of potential evapotranspiration or soil erosion. The analyses reveal long-term trends and inter-annual yield variability in the EPIC-based GGCMs to be highly sensitive to soil parameterization and crop management. Absolute yield levels as well depend not only on nutrient supply but 50 also on the parameterization and distribution of crop cultivars. All GGCMs show an intermediate performance in reproducing reported absolute yield levels or inter-annual dynamics. Our findings suggest that studies focusing on the evaluation of differences in bio-physical routines may require further harmonization of input data and management assumptions in order to eliminate background noise resulting from differences in model setups. For agricultural impact assessments, employing a GGCM ensemble with its widely varying assumptions 55 in setups appears the best solution for bracketing such uncertainties as long as comprehensive global datasets taking into account regional differences in crop management, cultivar distributions and coefficients for parameterizing agro-environmental processes are lacking. Finally, we recommend improvements in the documentation of setups and input data of GGCMs in order to allow for sound interpretability, comparability and reproducibility of published results

    The Origins of Bagan: The archaeological landscape of Upper Burma to AD 1300.

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    The archaeological landscape of Upper Burma from the middle of the first millennium BC to the Bagan period in the 13th-14th century AD is a landscape of continuity. Finds of polished stone and bronze artifacts suggest the existence of early metal-using cultures in the Chindwin and Samon River Valleys, and along parts of the Ayeyarwady plain. Increasing technological and settlement complexity in the Samon Valley suggests that a distinctive culture whose agricultural and trade success can be read in the archaeological record of the Late Prehistoric period developed there. The appearance of the early urban "Pyu" system of walled central places during the early first millennium AD seems to have involved a spread of agricultural and management skills and population from the Samon. The leaders of the urban centres adopted Indic symbols and Sanskrit modes of kingship to enhance and extend their authority. The early urban system was subject over time to a range of stresses including siltation of water systems, external disruption and social changes as Buddhist notions of leadership eclipsed Brahmanical ones. The archaeological evidence indicates that a settlement was forming at Bagan during the last centuries of the first millennium AD. By the mid 11th century Bagan began to dominate Upper Burma, and the region began a transition from a system of largely autonomous city states to a centralised kingdom. Inscriptions of the 11th to 13th centuries indicate that as the Bagan Empire expanded it subsumed the agricultural lands that had been developed by the Pyu

    Non-Minimal Supersymmetric Higgs Bosons at LEP2

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    We discuss the discovery reach of LEP2 for the Higgs sector of a general extension of the MSSM including a single gauge singlet field. This change introduces a new quartic Higgs boson self-coupling which can increase the masses of the CP-even states, and also allows mixing between singlet and non-singlet states which can reduce the couplings of the mass eigenstates to the ZZ. The lightest CP-even Higgs boson is bounded by a parameter Λ\Lambda which takes a maximum value Λmax136146\Lambda_{max}\approx 136-146 GeV for top mass 150195150-195 GeV. We generalise the discussion of the bound to include the entire CP-even spectrum and show how experiment may exclude values of Λ\Lambda smaller than some Λmin\Lambda_{min}. CP-even Higgs boson searches at LEP2 will be able to exclude Λmin81105\Lambda_{min}\approx 81-105 GeV, depending on the machine parameters. We also present exclusion plots in the mAtanβm_A-\tan\beta plane, based on an analysis of CP-even, CP-odd and charged Higgs production processes at LEP2.Comment: Plain LaTeX, 33 pages, figures uuencoded and gzipped. Trivial changes and typos corrected for publication in Rhys Rev

    Fertility, Living Arrangements, Care and Mobility

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    There are four main interconnecting themes around which the contributions in this book are based. This introductory chapter aims to establish the broad context for the chapters that follow by discussing each of the themes. It does so by setting these themes within the overarching demographic challenge of the twenty-first century – demographic ageing. Each chapter is introduced in the context of the specific theme to which it primarily relates and there is a summary of the data sets used by the contributors to illustrate the wide range of cross-sectional and longitudinal data analysed
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