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Groundwater fluoride levels in villages of Southern Malawi and removal studies using bauxite

Sajidu, S.M.I.; Masamba, W.R.L.; Thole, B.; Mwatseteza, J.F. (Academic Journals, http://www.academicjournals.org/ijps, NaN, 2008)

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URI: http://hdl.handle.net/10311/1091

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Sajidu_IJPS_2008.pdf (732.1Kb)

The Southern African Regional Science Initiative (SAFARI 2000): wet season campaigns

Otter, L.B.; Scholes, R.J.; Dowty, P.; Privette, J.; Caylor, K.; Ringrose, S.; Mukelabai, M.; Frost, P.; Hanan, N.; Totolo, O.; Veenendal, E. (Wageningen Institute for Environment and Climate Research, http://library.wur.nl/, NaN, 2002)

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Abstract:

The Southern African Regional Science Initiative (SAFARI 2000) involved two wet season and one dry season field campaigns. This paper reports on the wet season campaigns. The first was conducted at five sites along the Kalahari Transect in Zambia (Kataba Forest) and Botswana (Pandamatenga, Maun, Okwa River Crossing, Tshane) during February 2000 and concentrated primarily on characterizing the land surface with respect to exchanges of matter and energy with the atmosphere. The second, conducted in February 2001, focused on fluxes of water, gases and energy between the canopy and the atmosphere at Maun, Botswana, and at Skukuza in the Kruger National Park, South Africa. Eddy covariance measurements at Skukuza and Maun were designed to collect a near-continuous record of the seasonality and inter-annual variability in savanna carbon, water and energy exchanges in representative savanna ecosystems. This paper gives brief descriptions of the sites, the measurements made, and the methods used. It highlights some preliminary results, particularly from the first campaign, and outlines the next stages of the SAFARI 2000 project

URI:

http://hdl.handle.net/10311/1031

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Otter_ Southern_africa_2002.pdf (1.002Mb)

Looking for progenitors: a molecular approach to finding the origins of an invasive weed

Bond, J.M.; Veenedaal, E.M.; Hornby, D.D.; Gray, A.J. (Kluwer Academic Publishers, http://www.springerlink.com, November 28, 2002)

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Abstract:

One of the major problems in determining the origin of invasive species is that often their arrival is unnoticed. Only when population levels increase is their presence noticed but by this time determining the point of arrival is confounded by the extensive spread of the species. Here we use molecular markers (ISSRs) to determine the origin of an invasive weed in the Kalahari region, a species for which several origins could be possible. We show that molecular markers can be useful tools in determining the origin of invasive species.

URI:

http://hdl.handle.net/10311/1025

Files in this item: 1

Bond_2002.pdf (2.049Mb)

Woody vegetation resource changes around selected settlement along aridity gradient in the Kalahari, Botswana

Sekhwela, M.B.M. (Elsevier Science Ltd, http://www.elsevier.com/locate/cag, July 22, 2002)

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Abstract:

This paper investigated changes in economically important woody vegetation resources around seven settlements located along an aridity gradient in the Kalahari. Available data at different rainfall levels were analysed for different vegetation aspects. Total woody plant density and number of species at each site increased with increasing rainfall level, while individual species density differed at each site irrespective of rainfall, due to other factors, for example, land use as indicated by high stump densities around old and high population settlements. Drought resulted in high mortality of certain species, increasing availability of fuelwood resource in the form of dead wood. However, prolonged drought from climatic changes could result in browse shortage, a vital resource in the Kalahari. There was generally low wood resource availability throughout the studied gradient, without any distinct relation to rainfall, reflecting the influence of other factors such as soils, land use and natural variability.

URI:

http://hdl.handle.net/10311/1024

Files in this item: 1

Sekhwela M.B.M_2002.pdf (552.9Kb)

Temperature-Emissivity separation with ASTER and LANDSAT 7 validation on the fringe of the Okavango Delta, Botswana

Gieske, A.S.; Wubett, M.T.; Timmermans, W.J.; Parodi, G.N.; Wolski, P.; Arneth, A. (SPIE, http://link.aip.org, NaN, 2004)

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Abstract:

Land surface temperatures are important in global change studies, in estimating radiation budget, heat balance studies and as control for climate models. Several algorithms for estimating land surface temperature and emissivity spectra for multispectral thermal infrared images were developed recently for use with data from the Advanced Spacebome Thermal Emission and Reflection Radiometer (ASTER) on the TERRA platform. Similar methods are also used with the MODIS instrument. In this study, surface temperature and broadband emissivities were determined from the five TIR channels of ASTER instrument in an area on the southern fringe of the Okavango Delta (Botswana). MODTRAN 4 was used to determine the necessary atmospheric corrections while software was developed to facilitate MODTRAN post-processing. The results were compared with micrometeorological observations from a flux tower, with a LANDSAT 7 image of the same day, and finally also with reported ASTER surface temperature and emissivities for the same image (high level ASTER product). Results indicate that the surface temperature depends rather sensitively on atmospheric transmissivity and relatively large temperature differences are found between results from imagery analysis and flux tower. No relation was found between broad-band emissivity and NDVI, contrary to earlier findings in Botswana.

URI:

http://hdl.handle.net/10311/1015

Files in this item: 1

gieske_procSPIE_2003_pw.pdf (317.2Kb)

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