Browsing Faculty of Natural Sciences by Title
Now showing items 1684-1703 of 2571
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On the primordial origin of the smoothing excess in the Planck temperature power spectrum in light of LSS data
(IOP Publishing, 2022)The Planck DR3 measurements of the temperature and polarization anisotropies power spectra of the cosmic microwave background (CMB) show an excess of smoothing of the acoustic peaks with respect to ΛCDM, often quantified ... -
On the road to per cent accuracy - V. The non-linear power spectrum beyond ΛCDM with massive neutrinos and baryonic feedback
(Oxford University Press, 2021-12)In the context of forthcoming galaxy surveys, to ensure unbiased constraints on cosmology and gravity when using non-linear structure information, per cent-level accuracy is required when modelling the power spectrum. This ... -
On the time delay between ultra-relativistic particles
(Elsevier, 2016)The time delay between the receptions of ultra-relativistic particles emitted simultaneously is a useful observable for both fundamental physics and cosmology. The expression of the delay when the particles travel through ... -
On the upper limit on stellar masses in the Large Magellanic Cloud cluster R136
(Oxford University Press, 2006)A truncated power-law distribution is fitted to the 29 largest stellar masses known in R136. Two different statistical techniques are used, with comparable results. An upper limit to the mass distribution of the order ... -
On the use of electrical resistivity methods in monitoring infiltration of salt fluxes in dry coal ash dumps in Mpumalanga, South Africa
(Water Research Commission, 2013)One of the principal environmental concerns relating to coal combustion waste disposal is the potential for groundwater contamination from salt fluxes and trace elements that may be leached into the underlying groundwater ... -
One- and Two-point source statistics from the LOFAR Two-metre sky survey first data release
(ESO, 2020)Context. The LOFAR Two-metre Sky Survey (LoTSS) will eventually map the complete Northern sky and provide an excellent opportunity to study the distribution and evolution of the large-scale structure of the Universe. Aims. ... -
One-pot synthesis and characterization of InP/ZnSe semiconductor nanocrystals
(Elsevier, 2013)We report on the one-pot synthesis of InP/ZnSe quantum dots (QDs) using a precursor-based colloidal synthesis in a noncoordinating solvent environment. The structural and optical studies were carried out on the as-prepared ... -
One-sided maximal inequalities for a randomly stopped bessel process
(Taylor & Francis Group, LLC, 2023)We prove a one-sided maximal inequality for a randomly stopped Bessel process of dimension (Formula presented.) For the special case when α = 1, we obtain a sharp Burkholder-Gundy inequality for Brownian motion as a ... -
The ongoing pursuit of R Coronae Borealis stars: the ASAS-3 survey strikes again
(EDP Sciences, 2013)CONTEXT: R Coronae Borealis stars( RCBs) are rare, hydrogen-deficient, carbon rich super giant variable stars that are likely the evolved merger products of pairs of CO and He white dwarfs. Only 55 RCB stars have been found ... -
An ontology for the south african protection of personal information act
(Curran Associates Inc., 2020)The protection and management of data, and especially personal information, is becoming an issue of critical importance in both the business environment and in general society. Various institutions have justifiable reasons ... -
Open user interconnect and quality of communication
(Telkom, 2004)We looked for and found two situations within the South African Digital Divide where constant and severe macro-scale latencies would most likely interfere with the usage of Information and Communication Technology (ICT) ... -
Opportunities for improving recognition of coastal wetlands in global ecosystem assessment frameworks
(Elsevier, 2021)Vegetated coastal wetlands, including seagrass, saltmarsh and mangroves, are threatened globally, yet the need to avert these losses is poorly recognized in international policy, such as in the Convention on Biological ... -
Opportunities in Africa for training in genome science
(Academic Journals, 2004)Genome science is a new type of biology that unites genetics, molecular biology, computational biology and bioinformatics. The availability of the human genome sequence, as well as the genome sequences of several other ... -
The optical polarization of the blazar PKS 2155–304 during an optical flare in 2010
(Oxford University Press, 2020)An analysis is presented of the optical polarimetric and multicolour photometric (BVRJ) behaviour of the blazar PKS 2155–304 during an outburst in 2010. This flare develops over roughly 117 d, with a flux doubling time τ ... -
Optical-faint, far-infrared-bright Herschel sources in the CANDELS fields: Ultra-luminous infrared galaxies at z > 1 and the effect of source blending
(American Astronomical Society, 2014)The Herschel very wide-field surveys have charted hundreds of square degrees in multiple far-IR (FIR) bands. While the Sloan Digital Sky Survey (SDSS) is currently the best resource for optical counterpart identifications ... -
The optically selected 1.4-GHz quasar luminosity function below 1 mJy
(Oxford University Press, 2020)We present the radio luminosity function (RLF) of optically selected quasars below 1 mJy, constructed by applying a Bayesian-fitting stacking technique to objects well below the nominal radio flux density limit. We test ... -
Optimal design of combined two-tank latent and metal hydrides-based thermochemical heat storage systems for high-temperature waste heat recovery
(Multidisciplinary Digital Publishing Institute (MDPI), 2020)The integration of thermal energy storage systems (TES) in waste-heat recovery applications shows great potential for energy efficiency improvement. In this study, a 2D mathematical model is formulated to analyze the ... -
An optimal portfolio and capital management strategy for basel III compliant commercial banks
(Hindawi Publishing Corporation, 2014)We model a Basel III compliant commercial bank that operates in a financial market consisting of a treasury security, a marketable security, and a loan and we regard the interest rate in the market as being stochastic. We ... -
Optimal strategy for controlling the spread of HIV/AIDS disease: A case study of South Africa
(Taylor and Francis Group, 2012)HIV/AIDS disease continues to spread alarmingly despite the huge amounts of resources invested infighting it. There is a need to integrate the series of control measures available to ensure a consistentreduction ... -
Optimisation of electrophoretic deposition parameters for gas diffusion electrodes in high temperature polymer electrolyte membrane fuel cells
(Elsevier, 2013)Electrophoretic deposition (EPD) method was used to fabricate gas diffusion electrodes (GDEs) for high temperature polymer electrolyte membrane fuel cells (HT PEMFC). Parameters related to the catalyst suspension and the ...