627 research outputs found

    Relationship Value, Trust And Supplier Retention In South African Automotive Supply Chains

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    Suppliers have a particular role to play in assuring competitiveness in supply chains. This article investigates the relationship between first and second tier suppliers in automotive supply chains in South Africa. Automotive component suppliers (first tier suppliers to assemblers (OEMS) such as Toyota) should make an extra effort to retain their suppliers (second tier), particularly suppliers of strategic parts, to assure the best value adding by the suppliers in the highly competitive supply chain landscape. To assure best value from suppliers they need to be retained in an active trusting, long term, collaborative relationship.  The more the customer trusts the supplier, the higher the perceived value of the relationship and the more likely parties will work together to retain the business relationship. The aim of this quantitative study amongst first tier suppliers is to obtain more insight into the relationships and the hierarchical correlation between the relationship value, trust and supplier retention in automotive supply chains in South Africa. With a regression analysis it was found that both trust and relationship value are substantial predictors of supplier retention, but trust is more important for supplier retention

    Advanced technologies for future ground-based, laser-interferometric gravitational wave detectors

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    We present a review of modern optical techniques being used and developed for the field of gravitational wave detection. We describe the current state-of-the-art of gravitational waves detector technologies with regard to optical layouts, suspensions and test masses. We discuss the dominant sources and noise in each of these subsystems and the developments that will help mitigate them for future generations of detectors. We very briefly summarise some of the novel astrophysics that will be possible with these upgraded detectors

    Stokes Diagnostis of 2D MHD-simulated Solar Magnetogranulation

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    We study the properties of solar magnetic fields on scales less than the spatial resolution of solar telescopes. A synthetic infrared spectropolarimetric diagnostics based on a 2D MHD simulation of magnetoconvection is used for this. We analyze two time sequences of snapshots that likely represent two regions of the network fields with their immediate surrounding on the solar surface with the unsigned magnetic flux density of 300 and 140 G. In the first region we find from probability density functions of the magnetic field strength that the most probable field strength at logtau_5=0 is equal to 250 G. Weak fields (B < 500 G) occupy about 70% of the surface, while stronger fields (B 1000 G) occupy only 9.7% of the surface. The magnetic flux is -28 G and its imbalance is -0.04. In the second region, these parameters are correspondingly equal to 150 G, 93.3 %, 0.3 %, -40 G, and -0.10. We estimate the distribution of line-of-sight velocities on the surface of log tau_5=-1. The mean velocity is equal to 0.4 km/s in the first simulated region. The averaged velocity in the granules is -1.2 km/s and in the intergranules is 2.5 km/s. In the second region, the corresponding values of the mean velocities are equal to 0, -1.8, 1.5 km/s. In addition we analyze the asymmetry of synthetic Stokes-V profiles of the Fe I 1564.8 nm line. The mean values of the amplitude and area asymmetry do not exceed 1%. The spatially smoothed amplitude asymmetry is increased to 10% while the area asymmetry is only slightly varied.Comment: 24 pages, 12 figure

    Toward scalable quantum computation with cavity QED systems

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    We propose a scheme for quantum computing using high-Q cavities in which the qubits are represented by single cavity modes restricted in the space spanned by the two lowest Fock states. We show that single qubit operations and universal multiple qubit gates can be implemented using atoms sequentially crossing the cavities.Comment: 14 pages, 8 figure

    Implementation of an Optimal First-Order Method for Strongly Convex Total Variation Regularization

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    We present a practical implementation of an optimal first-order method, due to Nesterov, for large-scale total variation regularization in tomographic reconstruction, image deblurring, etc. The algorithm applies to Ό\mu-strongly convex objective functions with LL-Lipschitz continuous gradient. In the framework of Nesterov both Ό\mu and LL are assumed known -- an assumption that is seldom satisfied in practice. We propose to incorporate mechanisms to estimate locally sufficient Ό\mu and LL during the iterations. The mechanisms also allow for the application to non-strongly convex functions. We discuss the iteration complexity of several first-order methods, including the proposed algorithm, and we use a 3D tomography problem to compare the performance of these methods. The results show that for ill-conditioned problems solved to high accuracy, the proposed method significantly outperforms state-of-the-art first-order methods, as also suggested by theoretical results.Comment: 23 pages, 4 figure

    Multi-gap superconductivity in a BaFe1.84Co0.16As2 film from optical measurements at terahertz frequencies

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    We measured the THz reflectance properties of a high quality epitaxial thin film of the Fe-based superconductor BaFe1.84_{1.84}Co0.16_{0.16}As2_2 with Tc_c=22.5 K. The film was grown by pulsed laser deposition on a DyScO3_3 substrate with an epitaxial SrTiO3_3 intermediate layer. The measured RS/RNR_S/R_N spectrum, i.e. the reflectivity ratio between the superconducting and normal state reflectance, provides clear evidence of a superconducting gap ΔA\Delta_A close to 15 cm−1^{-1}. A detailed data analysis shows that a two-band, two-gap model is absolutely necessary to obtain a good description of the measured RS/RNR_S/R_N spectrum. The low-energy ΔA\Delta_A gap results to be well determined (ΔA\Delta_A=15.5±\pm0.5 cm−1^{-1}), while the value of the high-energy gap ΔB\Delta_B is more uncertain (ΔB\Delta_B=55±\pm7 cm−1^{-1}). Our results provide evidence of a nodeless isotropic double-gap scenario, with the presence of two optical gaps corresponding to 2Δ/kTc\Delta/kT_c values close to 2 and 7.Comment: Published Versio

    In silico design of Phl p 6 variants with altered Fold-Stability significantly impacts antigen processing, immunogenicity and immune polarization

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    Introduction: Understanding, which factors determine the immunogenicity and immune polarizing properties of proteins, is an important prerequisite for designing better vaccines and immunotherapeutics. While extrinsic immune modulatory factors such as pathogen associated molecular patterns are well-understood, far less is known about the contribution of protein inherent features. Protein fold-stability represents such an intrinsic feature contributing to immunogenicity and immune polarization by influencing the amount of peptide-MHC II complexes (pMHCII). Here, we investigated how modulation of the fold-stability of the grass pollen allergen Phl p 6 affects its ability to stimulate immune responses and T cell polarization. Methods: MAESTRO software was used for in silico prediction of stabilizing or destabilizing point mutations. Mutated proteins were expressed in E. coli, and their thermal stability and resistance to endolysosomal proteases was determined. Resulting peptides were analyzed by mass spectrometry. The structure of the most stable mutant protein was assessed by X-ray crystallography. We evaluated the capacity of the mutants to stimulate T cell proliferation in vitro, as well as antibody responses and T cell polarization in vivo in an adjuvant-free BALB/c mouse model. Results: In comparison to wild-type protein, stabilized or destabilized mutants displayed changes in thermal stability ranging from −5 to +14°. While highly stabilized mutants were degraded very slowly, destabilization led to faster proteolytic processing in vitro. This was confirmed in BMDCs, which processed and presented the immunodominant epitope from a destabilized mutant more efficiently compared to a highly stable mutant. In vivo, stabilization resulted in a shift in immune polarization from TH2 to TH1/TH17 as indicated by higher levels of IgG2a and increased secretion of TNF-α, IFN-Îł, IL-17, and IL-21. Conclusion: MAESTRO software was very efficient in detecting single point mutations that increase or reduce fold-stability. Thermal stability correlated well with the speed of proteolytic degradation and presentation of peptides on the surface of dendritic cells in vitro. This change in processing kinetics significantly influenced the polarization of T cell responses in vivo. Modulating the fold-stability of proteins thus has the potential to optimize and polarize immune responses, which opens the door to more efficient design of molecular vaccines

    The Intentional Use of Service Recovery Strategies to Influence Consumer Emotion, Cognition and Behaviour

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    Service recovery strategies have been identified as a critical factor in the success of. service organizations. This study develops a conceptual frame work to investigate how specific service recovery strategies influence the emotional, cognitive and negative behavioural responses of . consumers., as well as how emotion and cognition influence negative behavior. Understanding the impact of specific service recovery strategies will allow service providers' to more deliberately and intentionally engage in strategies that result in positive organizational outcomes. This study was conducted using a 2 x 2 between-subjects quasi-experimental design. The results suggest that service recovery has a significant impact on emotion, cognition and negative behavior. Similarly, satisfaction, negative emotion and positive emotion all influence negative behavior but distributive justice has no effect

    Symmetries of a class of nonlinear fourth order partial differential equations

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    In this paper we study symmetry reductions of a class of nonlinear fourth order partial differential equations \be u_{tt} = \left(\kappa u + \gamma u^2\right)_{xx} + u u_{xxxx} +\mu u_{xxtt}+\alpha u_x u_{xxx} + \beta u_{xx}^2, \ee where α\alpha, ÎČ\beta, Îł\gamma, Îș\kappa and ÎŒ\mu are constants. This equation may be thought of as a fourth order analogue of a generalization of the Camassa-Holm equation, about which there has been considerable recent interest. Further equation (1) is a ``Boussinesq-type'' equation which arises as a model of vibrations of an anharmonic mass-spring chain and admits both ``compacton'' and conventional solitons. A catalogue of symmetry reductions for equation (1) is obtained using the classical Lie method and the nonclassical method due to Bluman and Cole. In particular we obtain several reductions using the nonclassical method which are no} obtainable through the classical method
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