Browsing Faculty of Natural Sciences by Title
Now showing items 1691-1710 of 2571
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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 ... -
Optimisation of SlotTime for a single-radio Mid-Range Multi-hop Wireless Mesh Network
(Telkom SA, 2014)This paper presents the business context and results of an optimisation exercise for a single-radio mid-range multi-hop wireless mesh network for the provision of VoIP services. This WiFi mesh network physically covers 30 ... -
Optimization of gas diffusion electrode for polybenzimidazole-based high temperature proton exchange membrane fuel cell: Evaluation of polymer binders in catalyst layer
(Elsevier, 2013)Gas diffusion electrodes (GDEs) prepared with various polymer binders in their catalyst layers (CLs) were investigated to optimize the performance of phosphoric acid doped polybenzimidazole (PBI)-based high temperature ... -
Optimization of the observing cadence for the Rubin observatory legacy survey of space and time: A pioneering process of community-focused experimental design
(IOP Publishing, 2022)Vera C. Rubin Observatory is a ground-based astronomical facility under construction, a joint project of the National Science Foundation and the U.S. Department of Energy, designed to conduct a multipurpose 10 yr ... -
Opto-electronic properties of anodized TiO2 nanotube arrays investigated using electron energy loss spectroscopy
(sciencedirect, 2019)A study of the nanoscale crystallinity of anodized TiO2 nanotubes is reported with the aim of demonstrating its influence on the localized optical and electronic properties of the structure. By employing scanning transmission ... -
Oral colonization of Gram-negative anaerobes as a risk factor for preterm birth
(Landes Bioscience, 2011)Preterm birth significantly impacts on neonatal morbidity and mortality and is apparently increasing worldwide. Several studies have attempted to define a causative role for periodontal disease in adverse pregnancy ... -
Oral health status and treatment needs of pregnant women attending antenatal clinics in KwaZulu-Natal, South Africa
(Hindawi, 2019)During pregnancy, the oral cavity is characterised by an acidic environment and an inflammatory response brought about by vomiting and changes in hormonal levels, respectively, thereby increasing the mother’s risk of ... -
The orbital periods of aa dor and ny vir
(Oxford University Press, 2011)New timings of eclipses made between 2000 and 2010 are presented for two binary systems with hot subdwarf primary stars. In the case of AA Dor, an sdOB star with a very cool secondary, the period is found to be constant ...