1,314 research outputs found

    A Risk-Adjusted Evaluation Of The JSE Top 40 As An International Investment Option

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    In response to the wealth destruction caused by the 2007/2008 global financial crisis, many developed economies have lowered their interest rates to improve their balance sheets (SARB, 2008-2012). However, in order for investors to sustain expected returns they will have to deviate from the traditional approach of investing in government bonds and consider investing in emerging markets, which are considered as potential drivers of global growth (Deloitte Consulting LLP, 2012). The goal of this paper is to establish the importance of considering South Africa as an emerging market investment opportunity, but also to acknowledge its ability of outperforming several other common emerging markets during the post-financial crisis period. This was done by means of a novel approach to the Omega ratio. The results from this paper confirms this, illustrating that the performance of the JSE Top 40 will compensate for the additional political risk that emerging market investments possess (Anshuman, 2010)

    Impact of ocean warming on sustainable fisheries management informs the Ecosystem Approach to Fisheries

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    Acknowledgements Serpetti N., Heymans J.J., and Burrows M.T. were funded by the Natural Environment Research Council and Department for Environment, Food and Rural Affairs under the Marine Ecosystems Research Programme (MERP) (grant No. NE/L003279/1). Baudron A. and Fernandes, P.G. were founded by Horizon 2020 European research projects MareFrame (grant No. 613571) and ClimeFish (grant No. 677039). Payne, B.L. was founded by the Natural Environment Research Council and Department for Environment under the ‘Velocity of Climate Change’ (grant No. NE/J024082/1).Peer reviewedPublisher PD

    Cluster Masses Accounting for Structure along the Line of Sight

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    Weak gravitational lensing of background galaxies by foreground clusters offers an excellent opportunity to measure cluster masses directly without using gas as a probe. One source of noise which seems difficult to avoid is large scale structure along the line of sight. Here I show that, by using standard map-making techniques, one can minimize the deleterious effects of this noise. The resulting uncertainties on cluster masses are significantly smaller than when large scale structure is not properly accounted for, although still larger than if it was absent altogether.Comment: 5 pages, 5 figure

    On the effect of image denoising on galaxy shape measurements

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    Weak gravitational lensing is a very sensitive way of measuring cosmological parameters, including dark energy, and of testing current theories of gravitation. In practice, this requires exquisite measurement of the shapes of billions of galaxies over large areas of the sky, as may be obtained with the EUCLID and WFIRST satellites. For a given survey depth, applying image denoising to the data both improves the accuracy of the shape measurements and increases the number density of galaxies with a measurable shape. We perform simple tests of three different denoising techniques, using synthetic data. We propose a new and simple denoising method, based on wavelet decomposition of the data and a Wiener filtering of the resulting wavelet coefficients. When applied to the GREAT08 challenge dataset, this technique allows us to improve the quality factor of the measurement (Q; GREAT08 definition), by up to a factor of two. We demonstrate that the typical pixel size of the EUCLID optical channel will allow us to use image denoising.Comment: Accepted for publication in A&A. 8 pages, 5 figure

    Can the Common Fisheries Policy achieve Good Environmental Status in exploited ecosystems : the west of Scotland demersal fisheries example

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    Alan R. Baudron, Niall G. Fallon and Paul G. Fernandes were funded by the Horizon 2020 European research project MareFrame (grant No. 613571). Natalia Serpetti and Johanna J. Heymans were funded by the Natural Environment Research Council and Department for Environment, Food and Rural Affairs under the Marine Ecosystems Research Programme (MERP) (grant No. NE/L003279/1). We thank two anonymous reviewers for their insightful comments.Peer reviewedPostprintPostprintPostprintPostprin

    The vacuum energy with non-ideal boundary conditions via an approximate functional equation

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    We discuss the vacuum energy of a quantized scalar field in the presence of classical surfaces, defining bounded domains ΩRd\Omega \subset {\mathbb{R}}^{d}, where the field satisfies ideal or non-ideal boundary conditions. For the electromagnetic case, this situation describes the conductivity correction to the zero-point energy. Using an analytic regularization procedure, we obtain the vacuum energy for a massless scalar field at zero temperature in the presence of a slab geometry Ω=Rd1×[0,L]\Omega=\mathbb R^{d-1}\times[0, L] with Dirichlet boundary conditions. To discuss the case of non-ideal boundary conditions, we employ an asymptotic expansion, based on an approximate functional equation for the Riemann zeta-function, where finite sums outside their original domain of convergence are defined. Finally, to obtain the Casimir energy for a massless scalar field in the presence of a rectangular box, with lengths L1L_{1} and L2L_{2}, i.e., Ω=[0,L1]×[0,L2]\Omega=[0,L_{1}]\times[0,L_{2}] with non-ideal boundary conditions, we employ an approximate functional equation of the Epstein zeta-function.Comment: 10 page

    Predicting chronic low-back pain based on pain trajectories in patients in an occupational setting: an exploratory analysis.

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    OBJECTIVE: This study aimed to (i) identify subpopulations of patients in an occupational setting who will still have or develop chronic low-back pain (LBP) and (ii) evaluate a previously developed prediction model based on the determined subpopulations. METHOD: In this prospective cohort, study data were analyzed from three merged randomized controlled trials, conducted in an occupational setting (N=622). Latent class growth analysis (LCGA) was used to distinguish patients with a different course of pain intensity measured over 12 months. The determined subpopulations were used to derive a definition for chronic LBP and evaluate an existing model to predict chronic LBP. RESULTS: The LCGA model identified three subpopulations of LBP patients. These were used to define recovering (353) and chronic (269) patients. None of the interventions showed a relevant treatment effect over another but the rate of decline in symptoms during the first months of the intervention seems to predict recovery. The prediction model, based on this dichotomous outcome, with the variables pain intensity, kinesiophobia and a clinically relevant change in pain intensity and functional status in the first three months, showed a bootstrap-corrected performance with an area under the operating characteristic curve (AUC) of 0.75 and explained variance of 0.26. CONCLUSION: In an occupational setting, different subpopulations of chronic LBP patients could be identified using LCGA. The prediction model based on these subpopulations showed a promising predictive performance
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