Browsing by Title
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Kumar, J.; Kumar, P.; Suri, N.; Ahmad, M.; Thangaraj, R.; Sathiaraj, T.S. ( NaN, 2008)[more][less]
Abstract: Optical properties of Pb doped ternary Ge-Sb-Te chalcognide films prepared by thermal evaporation have been studied in the visible and near-infrared spectral regions. The straightforward analysis proposed by Swanepoel has been successfully employed and it has allowed us to accurately determine the refractive index and extinction coefficient of the films. The refractive index has been determined from the upper and lower envelopes of the transmission spectra. The absorption coefficient and extinction coefficient have been determined from the transmission spectra in the strong-absorption region. The dispersion of the refractive index is discussed in terms of the Wemple–DiDomenico single oscillator model. URI: http://hdl.handle.net/10311/544 Files in this item: 1
Effect of composition.pdf (950.3Kb) -
Chaturvedi, P.; George, S.; Milinganyo, M.; Tripathi, Y.B. (John Wiley & Sons, Ltd, http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-1573, NaN, 2004)[more][less]
Abstract: In this study, the methanol extract of Momordica charantia fruit extract was administered to diabetic rats to assess the long term effect of the extract on the lipid profile and the oral glucose tolerance test. Treatment for 30 days showed a significant decrease in triglyceride, low density lipoprotein and a significant increase in high density lipoprotein level. A significant effect on oral glucose tolerance was also noted. Chronic administration showed an improvement in the oral glucose tolerance curve. The effect was more pronounced when the test was done in rats fed the extract on the day of the test compared with tests done in rats which were not fed the extract on the same day. URI: http://hdl.handle.net/10311/1017 Files in this item: 1
Chaturvedi_PR_2004.pdf (258.2Kb) -
Taiwo, A.A.; Tyolo, J.B. (Elsevier, http://www.elsevier.com/wps/find/homepage.cws_home, January 8, 2002)[more][less]
Abstract: Evidence abounds in the literature of a direct link between pre-primary education and academic performance in the primary school. The salutary effect of the ‘Head start’ programme inaugurated in the United States of America in the early 1960s on the academic performances of its beneficiaries in the lower primary is such a piece of evidence. Premised on this commonality between pre-primary education and academic achievement in the primary school, the study aimed at finding out whether there were significant differences in the performances of Botswana grade one pupils with preschool education experience and their counterparts without such an experience on selected tasks in English language, mathematics and science. Using purposive sampling technique for school selection, a total of 120 grade one pupils were randomly selected for the study from four selected primary schools in Botswana. In addition, 20 grade one teachers from the study schools participated in the study. For data collection purpose, each pupil-subject was individually interviewed for about 20 min on the study tasks; and the opinions of the twenty teachers on the subject of the study was sampled by the use of a questionnaire. The results of the study indicated that pupils with pre-school education experience significantly out-performed their counterparts without such experience in all the three school subject areas surveyed by the study. This trend of the impact of pre-school education on academic achievement at the early primary school level was corroborated by the opinions of the primary school teachers. The paper concluded by observing that preschool education equips children with pre-requisite skills which make learning in grade one easier and faster for children so exposed. URI: http://hdl.handle.net/10311/722 Files in this item: 1
Taiwo_IJED_2002.pdf (1.263Mb) -
Mahgoub, S.E.O.; Ahmed, B.M.; Ahmed, M.M.O.; El Agib, E.N.A.A. (Elsevier; www.elsevier.com/locate/foodchem, NaN, 1999)[more][less]
Abstract: The effect of fermentation, germination and heating on the levels of thiamine, riboflavin and some mineral elements was studied in Sudanese kisra bread and hulu-mur drink prepared from the two sorghum cultivars dabar and fetarita, consecutively. Fermentation of kisra increased riboflavin but decreased thiamine significantly (p<0.01), whereas fermentation of hulu-mur reduced the levels of both vitamins significantly (p<0.01). Germination of fetarita grains for 6 days caused a significant (p<0.01) increase of riboflavin (700%) and a significant (p<0.01) reduction of thiamine (42%). Riboflavin was not affected by baking of kisra and thiamine level was slightly reduced. Hulu-mur baking caused significant (p<0.01) reduction of both thiamine and riboflavin. Fermentation caused no significant effect (p<0.01) on the mineral contents of kisra or hulu-mur. Addition of spices to hulu-mur dough caused significant increases (p<0.01) of strontium (80%), calcium (60%) and iron (35%). Germination of fetarita grains caused significant increases (p<0.01) of zinc (90%), lead (65%) and molybdenum (58%). Baking of kisra and hulu-mur did not cause any significant loss (p<0.01) in the contents of minerals. URI: http://hdl.handle.net/10311/215 Files in this item: 2
license.txt (1.998Kb)Mahgoub_FC_1999.pdf (1.152Mb) -
Moseki, B.; Dintwe, K. (Global Science Books, http://www.globalsciencebooks.info/, NaN, 2011)[more][less]
Abstract: The effects of water stress on the photosynthetic characteristics of two locally-cultivated sorghum cultivars (‘Segaolane’ and ‘Town’) were investigated over a period of weeks. Water stress was imposed on 1-week-old plants by withholding water. Measurements of chlorophyll fluorescence were used to determine changes in the efficiency of light utilization for electron transport, the occurrence of photoinhibition of photosystem II photochemistry on the sorghum cultivars. Drought treatment significantly decreased leaf area in all species, an important factor in drought-induced decreases in photosynthetic productivity. Water-stressed ‘Town’ exhibited a decrease in maximum photochemical efficiency of PSII (estimated from dark-adapted Fν⁄Fм ratio) with increasing period of withholding water. Light-adapted Fν’⁄Fм’ estimated the efficiency of excitation energy transfer to open PSII centres. Water-stressed ‘Town’ displayed a decrease in the efficiency of excitation energy transfer to open PSII reaction centres throughout the entire study period. The quantum yield of PSII electron transport (фPSII), which represents electron flow beyond PSII, decreased markedly in water-stressed ‘Town’ compared with that of water-stressed ‘Segaolane’. These initial findings indicate that ‘Town’ is more prone to photoinhibition than ‘Segaolane’. URI: http://hdl.handle.net/10311/962 Files in this item: 1
Moseki_AJPSB_2011.pdf (96.03Kb) -
Murty, V.R.K. (Elsevier Science Ltd. www.elsevier.com/locate/radphyschem, NaN, 2004)[more][less]
Abstract: The study of interaction of photons with matter finds wide application in areas such as industry, medical radiation dosimetry and radiation shielding. A careful review of these measurements indicates that the studies are exhaustive in respect of pure elements. However, measurements on photon attenuation in alloys are meagre. This is mainly due to the difficulty in procuring targets in suitable form for experimentation. Such studies play a prominent role in selecting alternative shielding materials on the cost-effective basis. URI: http://hdl.handle.net/10311/268 Files in this item: 1
Murty_RPC71_2004.pdf (223.2Kb) -
Baliyan, S. (IJSRE, http://www.ijsre.com, September NaN, 2012)[more][less]
Abstract: This formative evaluation seeks to measure the effectiveness of Botswana ICT curriculum (Code 0417) by evaluating the content taught and the instructional strategies used to deliver the course contents. It also seeks to assess whether both academics and students felt that the course content and instructional strategies were important. This study employed both quantitative and qualitative research designs as surveys, focus groups, one-on-one interviews, classroom observations and student test annual examination grades were used to collect data. Sixty students enrolled in the course and twelve course instructors were selected randomly from a sample of three private senior secondary schools in Botswana. Descriptive statistical analyses were used to analyse the data collected. Students rated all ICT course topics, except computer networks, as less useful than did their instructors. Both students and teachers offered a number of suggestions on how this course might be improved. URI: http://hdl.handle.net/10311/1108 Files in this item: 1
Baliyan_IJSRE_2012.pdf (1.104Mb) -
Mladenov, N.; McKnight, D.M.; Wolski, P.; Ramberg, L. (The Society of Wetland Scientists, NaN, 2005)[more][less]
Abstract: In the Okavango Delta in Botswana, dissolved organic matter (DOM) transport is controlled by the slow movement of an annual flood ‘pulse’ across permanently and seasonally flooded wetlands, known respectively as the Permanent Swamp and Seasonal Swamp. We studied temporal and spatial variations in fluorescence index (FI) and specific UV absorbance (SUVA) of DOM to identify DOM sources and fate during the flood. Dissolved organic carbon (DOC) concentrations ranged from 2 to 25 mg C L21 in channels of the Delta, with seasonal floodplains having consistently higher concentrations. Chemical indices, such as DOC concentrations, conductivity, specific UV absorbance (SUVA), fluorescence, total dissolved nitrogen, and chlorophyll a, were analyzed for channel and floodplain sites in the Seasonal Swamp. DOC concentrations increased during the rising limb of the flood in the Seasonal Swamp. SUVA of whole water samples and fluorescence index (FI) of fulvic acids isolated from channel and floodplain sites changed in a manner indicating the release of DOM by leaching of plant litter during the flood. After the flood receded, DOC concentrations and fulvic acid content decreased, and microbially-derived sources of organic matter dominated. Along two river reaches, measuring over 400 km each, variations in DOC concentrations were primarily due to geomorphology, with the effects of the annual flood overprinted atop the spatial controls. Increasing downstream DOC concentrations were found to be a product of inundation of DOC-rich seasonal floodplains and evaporation-enriched waters downstream. Increasing SUVA, dissolved nitrogen, and fulvic acid content, and decreasing FI downstream suggested microbial processing of terrestrial DOM and possible release of nutrients incorporated in the DOM. URI: http://hdl.handle.net/10311/526 Files in this item: 1
Mladenov2005FLOODynamics.pdf (2.529Mb) -
Pansiri, J. (Elsevier Science B.V., Amsterdam.; www.elsevier.com/locate/tourman, NaN, 2008)[more][less]
Abstract: This study examines the effects of characteristics of alliance partners on perceived strategic alliance performance. Alliance relationships were explored within and between the travel sector, and other tourism sectors of accommodation and transport. Study results indicate company executives' high level of satisfaction with alliances performance. Commitment and capability has been found to positively influence general satisfaction with alliance performance, market share and profitability, and overall alliance performance while trust positively influence general satisfaction with alliance performance. Control was found to have an influence on satisfaction with technology transfer and alliance operational performance while compatibility was positively associated with general satisfaction with alliance performance. URI: http://hdl.handle.net/10311/79 Files in this item: 2
license.txt (1.998Kb)Pansiri_TM_2008.pdf (5.794Mb) -
Chaturvedi, P.; Segale, M. (Academic Journals http://www.academicjournals.org/SRE/index.htm, NaN, 2007)[more][less]
Abstract: Four types of extracts were prepared from Melia azedarach fruits. These were methanol extract and three types of water decoctions; urine treated water decoction (UE), milk treated water decoction (ME) and plain water decoction (WE). Different doses of these four extracts were tried in normal rats to estimate the hypoglycemic activity of these extracts against glucose induced hyperglycemia. Most potent doses of all the extracts were assessed for their effects on lipid peroxidation, toxic effects on liver and reduced glutathione which is considered as first line of defense against free radicals in normal rats after 10 days of oral administration. All the extracts were found to posses hypoglycemic properties. Methanol extract showed toxic effects on the liver as indicated by high activities of Serum glutamate oxaloacetate (SGOT) and serum glutamate pyruvate tranasaminase (SGPT). It also indicated high rate of lipid peroxidation and depleted reduced glutathione levels of plasma. On the other hand three water decoctions showed very low activities of SGOT, SGPT, very low rates of lipid peroxidation and high levels of reduced glutathione. Extract prepared by the Ayurvedic method reduce blood glucose in glucose induced hyperglycemic rats and impart no toxicity. URI: http://hdl.handle.net/10311/181 Files in this item: 2
Effects of different types of water.pdf (836.9Kb)license.txt (1.998Kb) -
Brooks, C.; Bonyongo, C.; Harris, S. (Wildlife Society http://joomla.wildlife.org/index.php?option=com_content&task=view&id=43, NaN, 2008)[more][less]
Abstract: Global Positioning System (GPS) collars are increasingly being used to study fine-scale patterns of animal behavior. Previous studies on GPS collars have tried to determine the causes of location error without attempting to investigate whether the accuracy of fixes provides a correspondingly accurate measure of the animal's natural behavior. When comparing 2 types of GPS collar, we found a significant effect of collar weight and fit on the rate of travel of plains zebra (Equus burchelli antiquorum) females in the Makgadikgadi, Botswana. Although both types of collar were well within accepted norms of collar weight, the slightly heavier collars (0.6% of total body mass [TBM]) reduced rate of travel by >50% when foraging compared with the collar that was 0.4% of TBM. Collar effect was activity specific, particularly interfering with grazing behavior; the effect was less noticeable when zebras crossed larger interpatch distances. We highlight that small differences in collar weight or fit can affect specific behaviors, limiting the extrapolation of fine-scaled GPS data. This has important implications for wildlife biologists, who hitherto have assumed that collars within accepted weight limits have little or no effect on animal movement parameters. URI: http://hdl.handle.net/10311/628 Files in this item: 1
Brooks_JWM_2008.pdf (1.039Mb) -
Mpoloka, S.W. (Academic Journals. http://www.academicjournals.org/AJB, NaN, 2008)[more][less]
Abstract: Over the past few decades, there has been a depletion of the stratospheric ozone layer due to emissions of halogen-containing compounds of anthropogenic origin. This has resulted in a concomitant increase in solar ultraviolet-B radiation. High levels of UV-B radiation are responsible for multiple biologically harmful effects in both plants and animals. In plants, these effects include DNA damage, which often causes heritable mutations affecting various physiological processes, including the photosynthetic apparatus, protein destruction and signal transduction via UV-B photoreceptors. High UV-B levels introduce a number of different lesions, predominantly cyclobutane pyrimidine dimmers (CPDs) and pyrimidine (6-4) pyrimidinone products [(6-4) PPs] in the genome. These could adversely affect plant growth, development and morphology, especially the productivity of sensitive crop species. This paper reviews the genetic effects of long-term UV-B exposure in plants. URI: http://hdl.handle.net/10311/491 Files in this item: 1
Effects of prolonged.pdf (2.345Mb) -
Siele, M.P.; Mubyana-John, T.; Bonyongo, M.C. (Global Science Books http://www.globalsciencebooks.com/index.php?page=shop.product_details&category_id=1&flypage=shop.flypage&product_id=5&option=com_virtuemart&Itemid=56&vmcchk=1&Itemid=56, NaN, 2008)[more][less]
Abstract: Soil cover influences soil biological and chemical processes in various ways. The effects of soil cover (bare soil without litter, litter cover, Mopane tree canopy and grass cover) on soil respiration and microbial population at four sites in the Mopane woodland of north western Botswana were investigated. Soil respiration rates were measured using an infrared gas analyzer. Nitrifying bacterial populations were quantified by MPN on ammonium and nitrite calcium carbonate media, oligotrophs on 1% nutrient agar, actinomycetes on starch casein agar, bacteriovorous protozoans by MPN on sodium chloride agar baited with Enterobacter, and fungal biomass carbon using buried slides were also determined. Soil respiration in different habitats was significantly influenced by type of cover, diurnal temperature variations and soil moisture. Soils under cover showed significantly higher soil respiration than the bare soils. Autochthonous bacterial populations in the Mopane woodland soils consisted mostly of oligotrophs which varied insignificantly between seasons. Fungi were the most dominant microorganisms in all the Mopane woodland soils, with biomass of 162.05 to 282.14 μg C/g soil in the wet season and 11.84 to 44.16 μg C/g soil in the dry season. Microscopic observation of buried slides revealed that fungi play a vital role in holding soil particles together in these soils. The results showed a strong positive relationship between changes in fungal biomass and fluctuation of soil respiration. However, no clear correlation was observed between the variation of soil respiration and other microbial populations (oligotrophic bacteria, actinomycetes, and nitrifying bacteria). Overall these results indicate that in soils under Mopane tree canopy, fungi contribute significantly to soil structure and soil respiration. Other microbial populations consist mostly of oligotrophs which show minimal seasonal variations. Soil moisture significantly influences seasonal fluctuation in soil respiration. URI: http://hdl.handle.net/10311/292 Files in this item: 1
The Effects of Soil Cover.pdf (6.625Mb) -
Abadjieva, T. (University of Botswana, NaN, 1998)[more][less]
Abstract: Investigations of the influence of various factors on the modulus of elasticity and deformability of different types of lightweight concrete are presented.The results show that the modulus are not constant and decrease with the increase of the level of applied stress. Aggregate proposity and volume fraction effects the modulus of elasticity and the modulus of deformability of concrete. Using different concrete mixes of varying strength, it was confirmed that the the modulus of elasticity and the comprehensive strength of concrete are directly proportioned. The modulus of elasticity per unit strength decreases with the age of concrete. As lightweight concrete is a heterogeneous, multiphase material, the volume fraction and modulus of elasticity of the principal constituents influence the modulus of elasticity of the composite material. URI: http://hdl.handle.net/10311/611 Files in this item: 1
Abajieva_BJT_1998.pdf (1.208Mb) -
Toteng, E.N. (Routledge http://dx.doi.org/10.1080/02508060802475415, NaN, 2008)[more][less]
Abstract: This article examines the adverse effects of a fragmented water management framework and the role of domestic water users on water conservation in Gaborone, the rapidly growing capital city of Botswana. There was a major drought in Botswana in 2004, which recurred in 2007. The drought seriously affected water availability in Gaborone, re-igniting the water conservation debate. Most urban households prior to 2004 did not practise water conservation, except in cases of enforced temporary measures, such as water restrictions and increased water tariffs imposed by the Water Utilities Corporation. From secondary evidence, the situation had not changed much in 2007. URI: http://hdl.handle.net/10311/363 Files in this item: 1
Toteng_WI_2008.pdf (851.6Kb) -
Mbaiwa, J.E.; Stronza, A.M. (Routledge (Taylor & Francis) www.routledge.com, January 19, 2010)[more][less]
Abstract: The Community-Based Natural Resource Management (CBNRM) program in Botswana aims to achieve biodiversity conservation and rural development in rich biodiversity areas like the Okavango Delta. CBNRM assumes that if rural communities derive benefits from natural resources, they will be obliged to use such resources sustainably. Using the sustainable livelihoods framework, this study analyzes the effects of tourism development through CBNRM on rural livelihoods at Khwai, Sankoyo and Mababe in the Okavango Delta, Botswana, using primary and secondary data sources. Results of long-term surveys and in-depth interviews indicate that the three communities have forgone traditional livelihood activities such as hunting and gathering, livestock and crop farming to participate in tourism through CBNRM. Livelihoods in these villages have been improved as a result. Basic needs such as shelter, employment and income and social services like water supply systems, transportation, scholarships and payment of funeral expenses are now provided to community members and funded with income from CBNRM. Social capital has been built up in order to agree, manage and develop the CBNRM process. These results show that tourism development in these villages is achieving its goal of improved livelihoods, contradicting claims that community development projects are failing to achieve rural development. URI: http://hdl.handle.net/10311/960 Files in this item: 1
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Mbaiwa, J.E.; Mbaiwa, O.I. (International Journal of Wilderness; http://ijw.wilderness.net/, December NaN, 2006)[more][less]
Abstract: This article examines the effects of veterinary fences on wildlife populations in the Okavango Delta, Botswana. Using data from secondary data sources, findings indicate that the existence of veterinary fences in the Okavango Delta contributes to the decline of wildlife species in Botswana. Veterinary fences are erected to control the spread of livestock diseases in order to protect the European Union beef market where Botswanaâ s beef is largely exported. Migratory wildlife species such as wildebeests, zebras, giraffes, buffalo, and tsessebes have their migratory routes blocked by veterinary fences and hence die from dehydration and entanglements in the fence. Those that get trapped by the fence often become easy kill targets for poachers. Some of the animals have been observed walking along the fence trying to cross. The erection of veterinary fences indicates that the expansion of livestock production into wildlife areas threaten the survival of wildlife in Botswana. To address the problem, an integration of wildlife production with other sectors such as agricultural development should be made a priority at national and local policy levels. This means that the principles of sustainability should be given priority in the erection of veterinary fences in wildlife areas. URI: http://hdl.handle.net/10311/28 Files in this item: 2
license.txt (1.998Kb)mbaiwa_int_j_wilderness_2006.pdf (338.1Kb) -
Mazimba, O.; Masesane, I.B.; Majinda, R.R. (Elsevier Science Ltd, http://www.elsevier.com/locate/tetlet, NaN, 2011)[more][less]
Abstract: An efficient total synthesis of flavans from the reactions of salicylaldehyde and acetophenone derivatives is reported. The synthesis involves preparation of chalcones through an aldol reaction followed by reduction of both the double bond and the ketone using NaBH4 and an acetic acid mediated cyclization. Methoxy groups on the aromatic rings did not affect significantly the yields of the procedure. URI: http://hdl.handle.net/10311/1027 Files in this item: 1
Mazimba_TL_2011.pdf (204.0Kb) -
Forcheh, N. (Wiley-Blackwell, www.wiley.com/wiley-blackwell, NaN, 2002)[more][less]
Abstract: Summary. Ehrenberg presented the simple law-like relationship log(w) = 0.8h + 0.4 ? 0.04 between the weight and height of children aged 5-13 years. Several researchers have confirmed that this relationship holds, irrespective of the child's ethnic, racial, gender and social class. In anthropometry, a weight-height relationship is used to measure the nutritional status of children. For this purpose, the World Health Organization have adopted the National Center for Health Statistics population as the international reference population. The relationship between the World Health Organization-National Center for Health Statistics anthropometric standards and Ehrenberg law-like relationship is examined. Differences between the weight-for-height relationship in anthropometry and the law-like relationship between weight and height for children are small and can be attributable to functional differences. It is found that an Ehrenberg law-like relationship can be extended to include children who are under 5 years old. Criteria for using the law-like relationship to assess the nutritional status of these children are thus suggested. The criteria are evaluated using anthropometric data of a sample of 513 children from a rural district of Botswana. The results indicate that the proposed method of using the law-like relationship to assess nutritional status is much simpler and at least as reliable as the existing methods in anthropometry. Description: Symbols on the abstract may differ from the original abstract URI: http://hdl.handle.net/10311/1055 Files in this item: 1
Forcheh_JRSS.A_2002.pdf (2.588Mb) -
Masale, M. (Elsevier Science Ltd. http://www.elsevier.com/wps/find/journaldescription.cws_home/622948/description#description, NaN, 2008)[more][less]
Abstract: A calculation is presented on the scattering rates of electrons via the bulk spectrum of longitudinal optical phonons near a current-carrying core of radius R employing the Frohlich interaction Hamiltonian. The electrons are mainly confined near the core by an electric potential and are also under the influence of the current-induced spatially inhomogeneous static azimuthal magnetic field. The external magnetic field lifts the double degeneracy of the non-zero electron's axial wave number (kz ) states, while that of the nonzero azimuthal quantum number (m) states is preserved. In fact, the kz < 0 electron's energy subbands are found to be characterized by minima in their variations with the field. The intrasubband scattering rates show a remarkable behavior in their variations with the field. First, for weak electric potential of the nanosystem, these exhibit a strong, nonetheless inharmonic, oscillatory behavior in their variations with the field. The oscillations are, however, smoothed out as the strength of the electrical potential is increased, commencing at lower values of the field, within the same range of values of the field used. Second, for the same strength of the electric potential, there arise phase variations of the scattering rates in their variations with the field, resulting from the variation in the electron's axial wave number. URI: http://hdl.handle.net/10311/232 Files in this item: 2
license.txt (1.998Kb)Masale_SM_2008.pdf (1.267Mb)