Browsing Faculty of Natural and Agricultural Sciences by Title
Now showing items 2541-2560 of 4825
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LC-ESI/MS/MS analysis of neonicotinoids in urine of very low birth weight infants at birth
(PLoS, 2019)Objectives Neonicotinoid insecticides are widely used systemic pesticides with nicotinic acetylcholine receptor agonist activity that are a concern as environmental pollutants. Neonicotinoids in humans and the environment ... -
Lead exposure in raptors from Japan and source identification using Pb stable isotope ratios
(Elsevier, 2017)Lead (Pb) poisoning is widespread among raptors and water birds. In Japan, fragments of Pb ammunition are still found in endangered eagles although more than 10 years have passed since legislation regarding use of Pb ... -
Leadership behaviour preferences of student-athletes: a comparative study of South Africa and India
(Mediterranean Center of Social and Educational Research (MCSER), 2013)The athlete-coach relationship is a vertical dyadic relationship in which the coach plays a critical leadership role. The direct influence of coaches on their athletes has been widely reported in many studies from various ... -
Leapfrogging into new territory: how Mascarene ridged frogs diversified across Africa and Madagascar to maintain their ecological niche
(Elsevier, 2017)The Mascarene ridged frog, Ptychadena mascareniensis, is a species complex that includes numerous lineages occurring mostly in humid savannas and open forests of mainland Africa, Madagascar, the Seychelles, and the Mascarene ... -
Leerbestuurstelsels teenoor sosialenetwerk–omgewings: die ontwikkeling van n geïntegreerde tegnologiese onderrig–leer–model
(Universiteit van Stellenbosch, 2013)The use of computer - mediated communication (CMC), e.g. e-mail and text-based conferencing, particularly in asynchronous mode, has rapidly increased within higher education. Findings from the educational research literature ... -
Left ventricular mass and urinary metabolomics in young black and white adults: the African-PREDICT study
(Elsevier, 2020)Background and aims Increased left ventricular mass is an independent predictor for cardiovascular events, and shown to be higher in black than white populations. To gain a better understanding of early factors contributing ... -
Leisure time physical activity participation in women (30-65 years) with high coronary heart disease risk indicators
(AFAHPER-SD, 2011)The aim of this study was to determine the effect of leisure time physical activity participation (LTPA) on South African women presenting with some enhanced coronary heart disease (CHD) risk indicators (physical inactivity, ... -
Leptonic and hadronic modeling of Fermi-detected blazars
(IOP Science, 2013)We describe new implementations of leptonic and hadronic models for the broadband emission from relativistic jets in active galactic nuclei in a temporary steady state. For the leptonic model, a temporary equilibrium between ... -
Leptonic and hadronic modeling of Fermi-LAT hard spectrum quasars and predictions for high-energy polarization
(IOP Publishing, 2018)We present the results of a study of the time-averaged spectral energy distributions (SEDs) of eight flat spectrum radio quasars (FSRQs) present in the second catalog of high energy sources detected beyond 50 GeV by the ... -
Leptonic and lepto-hadronic modeling of the 2010 November flare from 3C 454.3
(AAS, 2016)In this study, we use a one-zone leptonic and a lepto-hadronic model to investigate the multi-wavelength emission and prominent flare of the flat spectrum radio quasar 3C 454.3 in 2010 November. We perform a parameter study ... -
Lessons from parasitic flatworms about evolution and historical biogeography of their vertebrate hosts
(Elsevier Masson SAS, 2009) -
Lessons on evolution from the study of edaphic specialization
(Springer, 2018)Plants adapted to special soil types are ideal for investigating evolutionary processes, including maintenance of intraspecific variation, adaptation, reproductive isolation, ecotypic differentiation, and the tempo and ... -
Lethal and sublethal impacts of a micropredator on post-settlement Caribbean reef fishes
(Springer, 2019)The transition from a planktonic larval stage to a benthic or demersal juvenile stage, “recruitment”, is a crucial event in the life history of coral reef fishes, and has a strong influence on population size. Predation ... -
Leukocyte telomere length and hemostatic factors in a South African cohort: the SABPA study
(Wiley, 2014)Background Incident atherothrombotic disease is predicted by leukocyte telomere length, a marker of biological age, and hemostatic factor levels, indicating a hypercoagulable state. We hypothesized that shorter telomeres ... -
Level of job satisfaction amongst nurses in the North-West Province, South Africa: Post occupational specific dispensation
(AOSIS, 2016)Background: Job satisfaction and burnout have been recurring problems amongst nurses in the Republic of South Africa (RSA). As a result, nurses are still leaving the rural public sector in search of lucrative work at the ... -
Levels of DNA methylation and transcript accumulation in leaves of transgenic maize varieties
(Springer, 2016)Background: Prior to their release in the environment, transgenic crops are examined for their health and environ‑ mental safety. In addition, transgene expression needs to be consistent in order to express the introduced ... -
Levels of PCBs in wild bird eggs: considering toxicity through enzyme induction potential and molecular structure
(ELSEVIER, 2013)Polychlorinated biphenyls (PCBs) were analysed in wild bird eggs from industrialised areas in South Africa. The concentration, congener profile, feeding guild, potential associated risk and biology were investigated. PCBs ... -
Lie group classification for a generalised coupld lane–emden system in dimension one
(2014)n this article, we discuss the generalised coupled Lane-Emden system u''+H(v)=0, v''+G(u)=0 that applies to several physical phenomena. The Lie group classification of the underlying system shows that it admits a ten-dimensional ... -
Lie symmetry analysis, conservation laws and exact solutions of the seventh-order time fractional Sawada-Kotera-Ito equation
(Elsevier, 2016)In this paper Lie symmetry analysis of the seventh-order time fractional Sawada-Kotera-Ito (FSKI) equation with Riemann-Liouville derivative is performed. Using the Lie point symmetries of FSKI equation, it is shown that ... -
Lie symmetry reductions and exact solutions of an option-pricing equation for large agents
(Springer, 2016)In this paper, we study a nonlinear partial differential equation that models the one-factor term structure option-pricing for large agents from the Lie symmetry stand point. This equation was modelled by Jonsson and Keppo ...