Search Results - "Cilliers, P."

Comparison of Ground‐Based Ionospheric Scintillation Observations With In Situ Electron Density Variations as Measured by the Swarm Satellites by Olwendo, J., Cilliers, P. J., Ming, Ou

“…Ionospheric scintillation is known to be associated with irregularities in electron density, which manifests as rapid fluctuations in the amplitude and phase…”
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Modelling the historical distribution of schistosomiasis-transmitting snails in South Africa using ecological niche models by Ayob, Nisa, Burger, Roelof P, Belelie, Monray D, Nkosi, Ncobile C, Havenga, Henno, de Necker, Lizaan, Cilliers, Dirk P

“…Schistosomiasis is a vector-borne disease transmitted by freshwater snails and is prevalent in rural areas with poor sanitation and no access to tap water…”
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What Future for Protected Areas? Analysing the Mismatch between South Africa’s Pre-existing Protected areas System and the Declared vision in Contemporary Conservation Policy by Alberts, R. C., Retief, F. P., Bond, A. J., Roos, C., Cilliers, D. P.

“…Designation of protected areas has enjoyed global application as a means of biodiversity conservation for over 100 years. National conservation policy is…”
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A framework for modelling spatio-temporal informal settlement growth prediction by Cilliers, P., van Vuuren, J.H., van Heerden, Q.

“…Many developing countries grapple with the problem of rapid informal settlement emergence and expansion. This exacts considerable costs from neighbouring urban…”
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Considering flood risk in spatial development planning : a land use conflict analysis approach by Cilliers, Dirk P.

“…Flooding is the predominant natural hazard observed in Africa, and it often leads to damage to property and losses in human lives. To ensure that the…”
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Gaining a deeper understanding of the psychology underpinning significance judgements in environmental impact assessment (EIA) by Retief, Francois P., Bond, Alan, Morrison-Saunders, Angus, Pope, Jenny, Alberts, Reece C., Roos, Claudine, Cilliers, Dirk P.

“…Significance judgements lie at the heart of EIA and provide the basis and justification for overall decision-making. Although the subjective nature of…”
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Three decades of EIA streamlining: Lessons from South Africa by Alberts, Reece C., Retief, Francois P., Roos, Claudine, Cilliers, Dirk P.

“…Due to high development demands, environmental impact assessment (EIA) systems internationally are under increasing pressure to simplify, streamline and…”
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A study on the variability of ionospheric total electron content over the East African low‐latitude region and storm time ionospheric variations by Olwendo, O. J., Yamazaki, Yosuke, Cilliers, P. J., Baki, P., Doherty, P.

“…The variation of total electron content (TEC) derived from the International Global Navigation Satellite Systems Service receiver (formerly IGS) over the East…”
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Proposing principles towards responsible waste management in South African protected areas by Roos, Claudine, Alberts, Reece C., Retief, Francois P., Cilliers, Dirk P., Bond, Alan J.

“…This article synthesises principles towards achieving responsible waste management in South African protected areas. These principles are distilled from and…”
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Measurements of biogenic volatile organic compounds at a grazed savannah grassland agricultural landscape in South Africa by Jaars, Kerneels, van Zyl, Pieter G, Beukes, Johan P, Hellén, Heidi, Vakkari, Ville, Josipovic, Micky, Venter, Andrew D, Räsänen, Matti, Knoetze, Leandra, Cilliers, Dirk P, Siebert, Stefan J, Kulmala, Markku, Rinne, Janne, Guenther, Alex, Laakso, Lauri, Hakola, Hannele

“…Biogenic volatile organic compounds (BVOCs) play an important role in the chemistry of the troposphere, especially in the formation of tropospheric ozone (O3)…”
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Applying inversion techniques to derive source currents and geoelectric fields for geomagnetically induced current calculations by de Villiers, J S, Cilliers, P J

“…This research focuses on the inversion of geomagnetic variation field measurement to obtain source currents in the ionosphere. During a geomagnetic…”
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Challenges and opportunities for sustainable solid waste management in private nature reserves: The case of Sabi Sand Wildtuin, South Africa by Roos, Claudine, Alberts, Reece C., Retief, Francois P., Cilliers, Dirk P., Hodgson, William, Olivier, Iain

“…The mismanagement of waste in protected areas may lead to significant and irreversible environmental, economic and social impacts, such as land degradation,…”
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A solar wind-based model of geomagnetic field fluctuations at a mid-latitude station by Lotz, S.I., Cilliers, P.J.

“…Anomalous quasi-DC currents known as geomagnetically induced currents (GIC), produced in electric power network infrastructure during geomagnetic storms, pose…”
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Storm-time characteristics of the equatorial ionization anomaly in the East African sector by Kassa, T., Damtie, B., Bires, A., Yizengaw, E., Cilliers, P.

“…•Storm-time E, neutral wind and composition can affect the EIA’s pattern.•Geomagnetic storms can intensify or suppress the EIA’s development.•The storm effect…”
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GPS phase scintillation at high latitudes during geomagnetic storms of 7–17 March 2012 – Part 2: Interhemispheric comparison by Prikryl, P, Ghoddousi-Fard, R, Spogli, L, Mitchell, C N, Li, G, Ning, B, Cilliers, P J, Sreeja, V, Aquino, M, Terkildsen, M

“…During the ascending phase of solar cycle 24, a series of interplanetary coronal mass ejections (ICMEs) in the period 7–17 March 2012 caused geomagnetic storms…”
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Interhemispheric comparison of GPS phase scintillation at high latitudes during the magnetic-cloud-induced geomagnetic storm of 5―7 April 2010 by PRIKRYL, P, SPOGLI, L, SPANSWICK, E, DONOVAN, E, WEATHERWAX, A. T, BRISTOW, W. A, ALFONSI, L, DE FRANCESCHI, G, ROMANO, V, NGWIRA, C. M, OPPERMAN, B. D. L, JAYACHANDRAN, P. T, KINRADE, J, MITCHELL, C. N, NING, B, LI, G, CILLIERS, P. J, TERKILDSEN, M, DANSKIN, D. W

“…Arrays of GPS Ionospheric Scintillation and TEC Monitors (GISTMs) are used in a comparative scintillation study focusing on quasi-conjugate pairs of GPS…”
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Estimating ionospheric currents by inversion from ground-based geomagnetic data and calculating geoelectric fields for studies of geomagnetically induced currents by de Villiers, J. S., Pirjola, R. J., Cilliers, P. J.

“…This research focuses on the inversion of geomagnetic variation field measurements to obtain the source currents in the ionosphere and magnetosphere, and to…”
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Nonlinear dynamic systems modeling using Gaussian processes: Predicting ionospheric total electron content over South Africa by Ackermann, E. R., de Villiers, J. P., Cilliers, P. J.

“…Two different implementations of Gaussian process (GP) models are proposed to estimate the vertical total electron content (TEC) from dual frequency Global…”
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Re-thinking the fundamentals of EIA through the identification of key assumptions for evaluation by Alberts, RC, Retief, FP, Roos, C, Cilliers, DP, Arakele, M

“…EIA is increasingly being questioned as a decision-making instrument of choice for decision makers. In addressing these concerns, the paper aims to re-think…”
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Low latitude ionospheric scintillation and zonal plasma irregularity drifts climatology around the equatorial anomaly crest over Kenya by Olwendo, O.J., Baki, P., Cilliers, P.J., Doherty, P., Radicella, S.

“…In this study we have used a VHF and GPS-SCINDA receiver located at Nairobi (36.8°E, 1.3°S, dip −24.1°) in Kenya to investigate the climatology of ionospheric…”
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