1,314 research outputs found
A Risk-Adjusted Evaluation Of The JSE Top 40 As An International Investment Option
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
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
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
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
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
We discuss the vacuum energy of a quantized scalar field in the presence of
classical surfaces, defining bounded domains ,
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 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 and
, i.e., 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.
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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