2,932 research outputs found

    A Review and Assessment of Enterprise Resource Planning for Make-To-Order Companies

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    Many vendors of Enterprise Resource Planning (ERP) systems claim that their products are widely applicable - configurable to meet the needs of any business, whatever the product or service offering. However, producers of high-variety and bespoke products, such as Make-To-Order (MTO) companies, present particular challenges to implementation; it remains unclear whether ERP systems can cater for their needs.. This paper provides a state-of-the-art review of ERP systems and an assessment of the applicability of ERP to the MTO sector. While several comprehensive reviews of the ERP literature have previously been presented, these either do not focus on the MTO sector, or seek to assess the applicability of ERP systems, or give sufficient attention to recent developments in the fast moving ERP industry. In assessing applicability, this paper considers factors such as the planning and control stages of relevance to MTO companies, the typical size and supply chain positioning of MTO companies, and market-related features. The assessment concludes that there is a significant gap between the requirements of MTO companies and the functionality of ERP systems. One such gap is between the customer enquiry management and design & engineering processes of MTO companies and those supported by ERP systems. Eight key areas in need of further research are described. These include: providing effective decision support tools for customer enquiry management activities in the MTO sector, linking ERP systems with production planning and control concepts of relevance to MTO companies, and conducting an in-depth empirical study into existing applications of ERP systems in MTO companies and their impact on performance

    Extending the Current Theorization On Cyberbullying: Importance of Including Socio-Psychological Perspectives

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    Despite an abundance of research from multiple perspectives and disciplines, to date cyberbullying research has been fragmented and is often conducted atheoretically, using theories borrowed from general psychology and/or criminology, or considers only individual-level explanations such as demographics, personalities, and psychological conditions which may be insufficient to fully understand and explain the behaviour. Social psychological approaches that examine the everyday power relations in children\u2019s lives and the study of identity, relationships, and belonging systems may provide meaningful context and a more holistic perspective. The purpose of this paper is to demonstrate the positive impact of applying identity theories and a sociological perspective to the study of cyberbullying. This paper provides an overview of cyberbullying, followed by examples of how general psychological theories and theories borrowed from criminology and aggression have been applied to cyberbullying, including a cyberbullying-specific theory. Several key theories of identity that could be employed in the study of cyberbullying are then identified. Lastly, the utility of using a socio-psychological perspective using social identity theory and social network analysis to study of cyberbullying is explored. In order to manage cyber violence, we need to act on multiple levels, including individual, relational, organizational, and community levels

    A test for within-lake niche differentiation in the nine-spined sticklebacks (Pungitius pungitius)

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    Specialization for the use of different resources can lead to ecological speciation. Accordingly, there are numerous examples of ecologically specialized pairs of fish species in postglacial lakes. Using a polymorphic panel of single nucleotide variants, we tested for genetic footprints of within-lake population stratification in nine-spined sticklebacks (Pungitius pungitius) collected from three habitats (viz. littoral, benthic, and pelagic) within a northern Swedish lake. Analyses of admixture, population structure, and relatedness all supported the conclusion that the fish from this lake form a single interbreeding unit.Peer reviewe

    Evolution of Fields in a Second Order Phase Transition

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    We analyse the evolution of scalar and gauge fields during a second order phase transition using a Langevin equation approach. We show that topological defects formed during the phase transition are stable to thermal fluctuations. Our method allows the field evolution to be followed throughout the phase transition, for both expanding and non-expanding Universes. The results verify the Kibble mechanism for defect formation during phase transitions.Comment: 12 pages of text plus 17 diagrams available on request, DAMTP 94-8

    Zurek-Kibble domain structures: The Dynamics of Spontaneous Vortex formation in Annular Josephson Tunnel Junctions

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    Phase transitions executed in a finite time show a domain structure with defects, that has been argued by Zurek and Kibble to depend in a characteristic way on the quench rate. In this letter we present an experiment to measure the Zurek-Kibble scaling exponent sigma. Using symmetric and long Josephson Tunnel Junctions, for which the predicted index is sigma = 0.25, we find sigma = 0.27 +/- 0.05. Further, there is agreement with the ZK prediction for the overall normalisation.Comment: To be published in Phys. Rev. Lett

    Density of Bloch Waves after a Quench

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    Production of Bloch waves during a rapid quench is studied by analytical and numerical methods. The density of Bloch waves decays exponentially with the quench time. It also strongly depends on temperature. Very few textures are produced for temperatures lower than a characteristic temperature proportional to the square of the magnetic field.Comment: 4 pages in RevTex + 3 .ps files; improved presentation; version to appear in PR

    Defect Formation and Critical Dynamics in the Early Universe

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    We study the nonequilibrium dynamics leading to the formation of topological defects in a symmetry-breaking phase transition of a quantum scalar field with \lambda\Phi^4 self-interaction in a spatially flat, radiation-dominated Friedmann-Robertson-Walker Universe. The quantum field is initially in a finite-temperature symmetry-restored state and the phase transition develops as the Universe expands and cools. We present a first-principles, microscopic approach in which the nonperturbative, nonequilibrium dynamics of the quantum field is derived from the two-loop, two-particle-irreducible closed-time-path effective action. We numerically solve the dynamical equations for the two-point function and we identify signatures of topological defects in the infrared portion of the momentum-space power spectrum. We find that the density of topological defects formed after the phase transition scales as a power law with the expansion rate of the Universe. We calculate the equilibrium critical exponents of the correlation length and relaxation time for this model and show that the power law exponent of the defect density, for both overdamped and underdamped evolution, is in good agreement with the "freeze-out" scenario of Zurek. We introduce an analytic dynamical model, valid near the critical point, that exhibits the same power law scaling of the defect density with the quench rate. By incorporating the realistic quench of the expanding Universe, our approach illuminates the dynamical mechanisms important for topological defect formation. The observed power law scaling of the defect density with the quench rate, observered here in a quantum field theory context, provides evidence for the "freeze-out" scenario in three spatial dimensions.Comment: 31 pages, RevTex, 8 figures in EPS forma

    The Hubble Diagram of Type Ia Supernovae in Non-Uniform Pressure Universes

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    We use the redshift-magnitude relation, as derived by D\c{a}browski (1995), for the two exact non-uniform pressure spherically symmetric Stephani universes with the observer positioned at the center of symmetry, to test the agreement of these models with recent observations of high redshift type Ia supernovae (SNIa), as reported in Perlmutter et al. (1997). By a particular choice of model parameters, we show that these models give an excellent fit to the observed redshifts and (corrected) B band apparent magnitudes of the SNIa data, but for an age of the Universe which is typically about two Gyr greater than in the corresponding Friedmann model. Based on a value of H065H_0 \sim 65 and assuming Λ0\Lambda \geq 0, the P97 data implies a Friedmann age of at most 13 Gyr and in fact a best-fit (for q0=0.5q_0 = 0.5) age of only 10 Gyr. Our Stephani models, on the other hand, can give a good fit to the P97 data with an age of up to 15 Gyr and could, therefore, significantly alleviate the conflict between recent cosmological and astrophysical age predictions. The choice of model parameters is quite robust: one requires only that the non-uniform pressure parameter, aa, in one of the models is negative and satisfies |a| \lte 3 km2^2 s2^{-2} Mpc1^{-1}. By allowing slightly larger, negative, values of aa one may `fine tune' the model to give an even better fit to the P97 data.Comment: 36 pages, 2 tables, 6 figures, AAS Latex 4.0, vastly revised version, new title and abstract, to appear in Ap

    Enhanced chlorhexidine skin penetration with 1,8-cineole

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    BACKGROUND: Chlorhexidine (CHG) penetrates poorly into skin. The purpose of this study was to compare the depth of CHG skin permeation from solutions containing either 2% (w/v) CHG and 70% (v/v) isopropyl alcohol (IPA) or 2% (w/v) CHG, 70% (v/v) IPA and 2% (v/v) 1,8-cineole. METHODS: An ex-vivo study using Franz diffusion cells was carried out. Full thickness human skin was mounted onto the cells and a CHG solution, with or without 2% (v/v) 1,8-cineole was applied to the skin surface. After twenty-four hours the skin was sectioned horizontally in 100 μm slices to a depth of 2000 μm and the concentration of CHG in each section quantified using high performance liquid chromatography (HPLC). The data were analysed with repeated measures analysis of variance. RESULTS: The concentration of CHG in the skin on average was significantly higher (33.3% [95%, CI 1.5% - 74.9%]) when a CHG solution which contained 1,8-cineole was applied to the skin compared to a CHG solution which did not contain this terpene (P = 0.042). CONCLUSIONS: Enhanced delivery of CHG can be achieved in the presence of 1,8-cineole, which is the major component of eucalyptus oil. This may reduce the numbers of microorganisms located in the deeper layers of the skin which potentially could decrease the risk of surgical site infection

    Quench Induced Vortices in the Symmetry Broken Phase of Liquid 4^4He

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    Motivated by the study of cosmological phase transitions, our understanding of the formation of topological defects during spontaneous symmetry-breaking and the associated non-equilibrium field theory has recently changed. Experiments have been performed in superfluid 4^4He to test the new ideas involved. In particular, it has been observed that a vortex density is seen immediately after pressure quenches from just below the λ\lambda transition. We discuss possible interpretations of these vortices, conclude they are consistent with our ideas of vortex formation and propose a modification of the original experiments.Comment: 29 pages, RevTeX with one EPS figur
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