2,769 research outputs found

    Measuring cosmological bulk flows via the kinematic Sunyaev-Zeldovich effect in the upcoming cosmic microwave background maps

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    We propose a new method to measure the possible large-scale bulk flows in the Universe from the cosmic microwave background (CMB) maps from the upcoming missions, MAP and Planck. This can be done by studying the statistical properties of the CMB temperature field at many X-ray cluster positions. At each cluster position, the CMB temperature fluctuation will be a combination of the Sunyaev-Zeldovich (SZ) kinematic and thermal components, the cosmological fluctuations and the instrument noise term. When averaged over many such clusters the last three will integrate down, whereas the first one will be dominated by a possible bulk flow component. In particular, we propose to use all-sky X-ray cluster catalogs that should (or could) be available soon from X-ray satellites, and then to evaluate the dipole component of the CMB field at the cluster positions. We show that for the MAP and Planck mission parameters the dominant contributions to the dipole will be from the terms due to the SZ kinematic effect produced by the bulk flow (the signal we seek) and the instrument noise (the noise in our signal). Computing then the expected signal-to-noise ratio for such measurement, we get that at the 95 % confidence level the bulk flows on scales >100h^{-1} Mpc can be probed down to the amplitude of <200< 200 km/sec with the MAP data and down to only 30 km/sec with the Planck mission.Comment: Astrophysical Journal Letters, in pres

    Residents\u27 perceptions of smart energy metres

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    Smart metres are a form of expert system with performance features beyond energy‐consumption record keeping, to include monitoring, analysing, and estimating metre readings. Although smart metres have great capabilities, this technology is still in its infancy in many developing countries, and little is known about the kinds of risks associated with smart metres from residents\u27 perspectives. This research therefore aims to fill this gap by examining the influence of four different types of perceived risk on residents\u27 intentions to use smart metres in Jordan. By following a quantitative approach, 242 survey responses were tested by using structural equation modelling–partial least squares. The statistical results indicated that perceived security and technical risks have a significant and negative impact on residents\u27 intentions to use smart metres. However, perceived privacy and health risks, surprisingly, were found to have no significant negative influence on intention to use. Theoretical and practical implications are indicated, and directions of future research are subsequently specified

    The structure of iterative methods for symmetric linear discrete ill-posed problems

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    The iterative solution of large linear discrete ill-posed problems with an error contaminated data vector requires the use of specially designed methods in order to avoid severe error propagation. Range restricted minimal residual methods have been found to be well suited for the solution of many such problems. This paper discusses the structure of matrices that arise in a range restricted minimal residual method for the solution of large linear discrete ill-posed problems with a symmetric matrix. The exploitation of the structure results in a method that is competitive with respect to computer storage, number of iterations, and accuracy.Acknowledgments We would like to thank the referees for comments. The work of F. M. was supported by DirecciĂłn General de InvestigaciĂłn CientĂ­fica y TĂ©cnica, Ministerio de EconomĂ­a y Competitividad of Spain under grant MTM2012-36732-C03-01. Work of L. R. was supported by Universidad Carlos III de Madrid in the Department of Mathematics during the academic year 2010-2011 within the framework of the Chair of Excellence Program and by NSF grant DMS-1115385

    Membrane shape as a reporter for applied forces

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    Recent advances have enabled 3-dimensional reconstructions of biological structures in vivo, ranging in size and complexity from single proteins to multicellular structures. In particular, tomography and confocal microscopy have been exploited to capture detailed 3-dimensional conformations of membranes in cellular processes ranging from viral budding and organelle maintenance to phagocytosis. Despite the wealth of membrane structures available, there is as yet no generic, quantitative method for their interpretation. We propose that by modeling these observed biomembrane shapes as fluid lipid bilayers in mechanical equilibrium, the externally applied forces as well as the pressure, tension, and spontaneous curvature can be computed directly from the shape alone. To illustrate the potential power of this technique, we apply an axial force with optical tweezers to vesicles and explicitly demonstrate that the applied force is equal to the force computed from the membrane conformation

    Disentangling the Effects of Corporate Disclosure on the Cost of Equity Capital: A Study of the Role of Intellectual Capital Disclosure

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    In this article, we investigate whether intellectual capital (IC) and financial disclosures jointly affect the firm’s cost of equity capital. In contrast to prior research, we disaggregate disclosures into IC and financial disclosures and examine whether the two disclosure types are jointly related to the cost of equity capital. We also investigate whether IC and financial disclosures have an interaction effect on the cost of equity capital. Using data for a sample of 125 U.K. firms, we find a negative relationship between the cost of equity capital and IC disclosure. We find that the relationship between financial disclosure and the cost of equity capital is magnified when combined with IC disclosure. In addition, we find that IC and financial disclosures interact in shaping their effects on the cost of equity capital. Further analyses suggest that the effect of financial disclosure on the cost of equity capital is augmented for firms characterized by a medium level of IC disclosure. These results provideimportant insights into the relationship between disclosures and cost of equity capital and have policy and practical implications

    Factors affecting SME owner-managers\u27 willingness to share knowledge online in rural local business networks

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    This article integrates typically separate SME research on e-commerce, business networking, and knowledge management into a model explaining factors influencing the willingness of SME owner-managers to share knowledge online in business networks in rural districts. This is important because e-commerce can assist owner-managers, often dispersed in rural districts, to share knowledge between face-to-face networking events. The main factors associated with willingness to share knowledge online were their willingness to share knowledge face-to-face and their intensity of Internet use. Entrepreneurial factors such as owner-managers\u27 expectations of rapid growth, trading outside the district, and seeking information about customers/competitors were indirectly associated with online sharing via intensity of Internet use only. The model suggests network coordinators could encourage online knowledge sharing by assisting owner-managers to see the business value of e-commerce and by ensuring that networking events are suitable for owner-managers, whether or not they have entrepreneurial goals, to facilitate face-to-face knowledge sharing
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