Browsing Faculty of Natural and Agricultural Sciences by Title
Now showing items 2805-2824 of 4825
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Modelling the effects of scattering parameters on particle-drift in the solar modulation of galactic cosmic rays
(Elsevier, 2015)It is well known that particle drift motions are suppressed by diffusive scattering as established by direct numerical simulations. The effect of constant scattering on the drift velocities of charged particles has always ... -
Modelling the formation of liver zones within the scope of fractional order derivative
(Hindawi Publishing Corporation, 2014)We develop and extend earlier results related to mathematical modelling of the liver formation zone by the adoption of noninteger order derivative. The hidden uncertainties in the model are captured and controlled thanks ... -
Modelling the growing population of y-ray millisecond pulsars
(Springer, 2011)TheFermiLarge Area Telescope, in collaboration with several groups from the radio community, have had marvellous success at uncovering new γ-ray millisecond pulsars (MSPs). In fact, MSPs now make up a sizable fraction of ... -
Modelling the light curves of Fermi LAT millisecond pulsars
(South African Institute of Physics, 2014)There are 40 millisecond pulsars (MSPs) in the second pulsar catalogue of the Fermi Large Area Telescope (LAT). This pulsar subpopulation is unique owing to their relatively small magnetospheres. This may result in radio ... -
Modelling the polarisation signatures detected from the first white dwarf pulsar AR Sco.
(Sissa Medialab, 2018)Marsh et al. (2016) detected radio and optical pulsations from the binary system AR Scorpii (AR Sco). This system, with an orbital period of 3.55 h, is composed of a cool, low-mass star and a white dwarf with a spin period ... -
Modelling the stellar soft-photon energy density of globular clusters
(South African Institute of Physics, 2014)Recent observations by e.g. Fermi LAT and H.E.S.S. have revealed globular clusters to be sources of high-energy and very-high-energy gamma rays. It has been suggested that the presence of large numbers of millisecond pulsars ... -
Modelling the y-ray and radio light curves of the double pulsar system
(South African Institute of Physics, 2014)Guillemot et al. recently reported the discovery [1] of -ray pulsations from the 22.7 ms pulsar (pulsar A) in the famous double pulsar system J0737−3039A/B. The -ray light curve (LC) of pulsar A has two peaks separated ... -
A model for the development and transformation of teachers' mathematical content knowledge
(Sabinet, 2012)In this paper we offer a theoretical discussion on the mathematical content knowledge development of secondary school mathematics teachers. We discuss relevant studies from literature and use different views and conceptions ... -
A modified groundwater flow model using the space time riemann–liouville fractional derivatives approximation
(Hindawi Publishing Corporation, 2014)The notion of uncertainty in groundwater hydrology is of great importance as it is known to result in misleading output when neglected or not properly accounted for. In this paper we examine this effect in groundwater flow ... -
Modified HEPES one-pot synthetic strategy for gold nanostars
(RSC, 2019)Gold nanostars are being used more regularly in the biosensing field. Despite their useful attributes, there is still a need to optimize aspects of the synthesis and stability. The seedless, synthetic method comprising ... -
Modified tests for exponentiality in the presence of Type II right censored data
(Wiley, 2019)The exponential distribution is one of the most popular choices of model, especially in survival analysis and reliability theory. Typically, to test the hypothesis that the underlying distribution of lifetimes are exponentially ... -
Modulation of galactic cosmic ray protons and electrons during an unusual solar minimum
(IOP Publishing, 2009)During the latest Ulysses out-of-ecliptic orbit the solar wind density, pressure, and magnetic field strength have been the lowest ever observed in the history of space exploration. Since cosmic ray particles respond to ... -
Modulation of galactic cosmic rays in a north-south asymmetrical heliosphere
(Elsevier, 2011)Observations made with the two Voyager spacecraft confirmed that the solar wind decelerates to form the heliospheric termination shock. Voyager 1 crossed this termination shock at ∼94 AU in 2004, while Voyager 2 crossed ... -
The modulation of galactic cosmic-ray electrons in the heliosheath
(IOP Publishing, 2010)Voyager 1 has observed strong increases in the intensities of 2-160 MeV electrons since crossing the termination shock of the heliosphere in 2004 December. Before this time these intensities were submerged below the detector ... -
Modulation of galactic electrons in the heliosphere during the unusual solar minimum of 2006-2009: a modeling approach
(IOP Publishing, 2015)The last solar minimum activity period, and the consequent minimum modulation conditions for cosmic rays, was unusual. The highest levels of Galactic protons were recorded at Earth in late 2009 in contrast to expectations. ... -
Modulation of galactic protons in the heliosphere during the unusual solar minimum of 2006 to 2009
(Springer Verlag, 2014)The last solar minimum activity period, and the consequent minimum modulation conditions for cosmic rays, was unusual. The highest levels of galactic protons were recorded at Earth in late 2009 in contrast to expectations. ... -
Modulation of specific inhibitory networks in fatigued locomotor muscles of healthy males
(Springer, 2018)Reduced maximal force capability of skeletal muscle, as a consequence of exercise, can be due to peripheral or central fatigue mechanisms. In upper-limb muscles, neuromuscular fatigue is concurrent with reduced corticospinal ... -
Molasses grass induces direct and indirect defense responses in neighbouring maize plants
(Springer, 2019)Plants have evolved intricate defence strategies against herbivore attack which can include activation of defence in response to stress-related volatile organic compounds (VOCs) emitted by neighbouring plants. VOCs released ... -
Molecular analysis of bacterial community dynamics during the fermentation of soy-daddawa condiment
(Springer, 2016)Bacterial community dynamics during soy-daddawa fermentation was investigated using culture-dependent and PCR-denaturing gradient gel electrophoresis (PCR-DGGE) molecular methods. The total titratable acidity (TTA), pH, ... -
A molecular analysis of the GBA gene in Caucasian South Africans with Parkinson's disease
(Wiley, 2017)Background The molecular basis of Parkinson's disease in South African population groups remains elusive. To date, substitutions in the GBA gene are the most common large-effect genetic risk factor for Parkinson's disease. ...