Showing papers by "University of Zambia published in 2000"

Analysis of genetic variation in Cucurbita moschata by random amplified polymorphic DNA (RAPD) markers.

Abstract: Knowledge of genetic relationships among genotypes is essential for the effective utilisation of germplasm, especially for poorly characterised species. Random amplified polymorphic DNA (RAPD) analysis provides a quick and reliable method for resolving genetic relationships. Although Cucurbita moschata Duch, also known as tropical pumpkin, is one of the most important vegetable crops in Africa, being adapted to a wide range of climatic and soil conditions, it is a scientifically neglected species. The objectives of this study were to (1) analyse the amount of genetic diversity inC. moschata landraces grown in south-central Africa and (2) classify the landraces to assist in selection of parent genotypes for improvement of fruit characteristics. Cluster analysis, based on 39 polymorphic and 105 monomorphic DNA fragments amplified by 16 primers, was used to show relationships among 31 genotypes obtained from Zambia and Malawi. The analysis revealed four clusters, with genotypes from Malawi mainly clustering in three clusters while all genotypes from Zambia and three from Malawi clustered in one cluster. The pair-wise mean genetic distance was 0.32 ± 0.04 for samples from Malawi and 0.26 ± 0.04 for samples from Zambia. The possible application of the resulting classification in breeding of C. moschata is discussed.

Character of channel planform change and meander development: Luangwa River, Zambia

Abstract: Air photo interpretation and field survey were used to examine rates and patterns of planform change over the last 40 years on an 80 km reach of the Luangwa River, Zambia. The river, a tributary of the Zambezi, is a 100–200 m wide, medium sinuosity sand-bed river (sinuosity index 1·84). High rates of channel migration (<33 m a−1) and cutoffs on meandering sections are frequent. Some meandering reaches, however, have remained relatively stable. A form of anastomosing with anabranches up to 14 km in length is also a characteristic. Patterns of meander development vary between bends but all can be described in relation to traditional geomorphic models; change occurs by translation, rotation, double-heading, concave bank bench formation and cutoff causing river realignment. At the local scale spatial variability in bank resistance, induced by floodplain sedimentology, controls rate of bank erosion, and valley-side channel ‘deflection’ is also apparent. Copyright © 2000 John Wiley & Sons, Ltd.

The equity impacts of community financing activities in three African countries.

Abstract: Although the Bamako Initiative from its very beginning was caught up in wider debates about the potential equity impact of any form of user financing, to date there has been little empirical investigation of this impact. This three-country study, undertaken in Benin, Kenya and Zambia in 1994/95, was initiated to add to the body of relevant evidence. It sought to understand not only what had been the equity impacts of community financing activities in these countries but also how they had been brought about. As a result, it investigated equity primarily through consideration of the design of these financing activities and through the perceptions of different actors, within a limited number of purposively selected geographical areas in each country, about their strengths and weaknesses. Additional data on utilization were either collected during the course of the study (Kenya) or drawn from other available studies (Benin and Zambia). Key issues considered in the studies' assessment of equity were the extent to which both relative and absolute affordability gains were achieved, as well as as an influence over both the distributional and procedural justice of the financing activities, the pattern of decision-making. Across countries there was evidence of relative affordability gains in Benin and Kenya, but Kenyan gains were not sustained over time and no such gains were identified in Zambia. In addition, no country had given attention either to the issue of absolute affordability, through the implementation of effective exemption mechanisms to protect the poorest from the burden of payment, or to the establishment of community decision-making bodies that effectively represented the interests of all groups including the poorest. Overall, therefore, although the Benin Bamako Initiative programme might be judged as successful in terms of what appear to be its own equity objectives, the other two countries' schemes had clear equity problems even in these terms. The experience across countries also highlights the unresolved question of whether equity is concerned with the greatest good for the greatest number or with promoting the interests of the most disadvantaged.

Delta Scuti Network observations of XX Pyx: detection of 22 pulsation modes and of short-term amplitude and frequency variations

Abstract: We report multisite observations devoted to the main-sequence δ Scuti star XX Pyx, conducted as the 17th run of the Delta Scuti Network. Over 125 nights a total of 550 h of usable time-series photometric B- and V-filter data were acquired involving both photoelectric and CCD measurements at eight observatories spread around the world, which represents the most extensive single time-series for any pulsating star other than the Sun obtained so far. We describe our observations and reduction methods, and present the frequency analysis of our new data. First, we detect six new pulsation and five new combination frequencies in the star's light curves. We also discover evidence for amplitude and/or frequency variations of some of the modes during the observations. These can occur on time-scales as short as 20 d and show quite diverse behaviour. To take them into account in the frequency analysis, a so-called non-linear frequency analysis method was developed, allowing us to quantify the temporal variability of the modes and to compensate for it. Following that we continue the frequency search and we also incorporate published multisite observations. In this way, we reveal three more pulsation and two more combination frequencies. In the end, we report a total of 30 significant frequencies – 22 of which correspond to independent pulsation modes. This is the largest number of independent modes ever detected in the light curves of a δ Scuti star. The frequencies of the modes show preferred separations as already suggested by previous work on this star; they are also arranged in clear patterns. These results lead to a refinement of the stellar mean density and to a new constraint on the rotation rate of XX Pyx (νrot=1.1±0.3 d−1). However, our attempts to identify the modes by pattern recognition failed. Moreover, mode identification from multicolour photometry failed as well because the high pulsation frequencies make this method unfavourable. The diverse behaviour of the amplitude and frequency variations of some of the modes leaves resonances as the only presently known possibility for their explanation.

Looking for change in response to the AIDS epidemic: trends in AIDS knowledge and sexual behavior in Zambia, 1990 through 1998.

Abstract: This study investigates trends in AIDS knowledge and sexual behavior among men and women in urban Lusaka 1990 to 1998, and in all of Zambia, 1992 to 1998. Using data from representative surveys of urban Lusaka and of the country as a whole, population proportions were estimated to examine trends in knowledge and sexual risk behaviors. Differences in the estimated proportions between 1990 and 1998 were tested in Lusaka. In all Zambia, tests of difference were conducted between the earliest and latest years for which data were available for each indicator. A decline in premarital sexual activity was observed in urban Lusaka. In 1990, 50% of never married women reported no sexual experience, compared with 60% in 1998 (p =. 003); among men, the figures were 38% and 53%, respectively (p <. 001). Fewer women (1990, 8%; 1998, 2%; p <.001) and men (1990, 31%; 1998, 19%; p =.07) had extramarital partners. The bulk of change observed in urban Lusaka took place from 1990 to 1996; the changes in men's behavior observed between 1996 and 1998 were also observed in the national estimates for those years. National figures for other indicators from 1992 to 1998 were less encouraging. Apart from an increase in having ever used condoms, no change in women's sexual behavior was observed. Fewer men had premarital sex from 1996 to 1998 (1996, 64%; 1998, 46%; p <.001), but condom use with nonregular partners decreased among men (1996, 38%; 1998, 29%; p =.02). Prevention campaigns focused on education about AIDS and promoting safer sexual behavior appear to have made a difference in the early 1990s in Zambia. Findings from more recent years indicate that further change has stagnated. Renewed efforts are needed, particularly targeting condom use with nonregular partners.

Detection and characterization of Clostridium species in soil of Zambia.

Abstract: In the retrospective study of soil-borne diseases of cattle in Zambia, malignant edema and blackquarter were widespread. One hundred and sixty-five cases with malignant edema and 103 cases with blackquarter were reported between 1985 and 1997. It was found that specific soil-conditions associate the emergence of the soil-borne diseases. Soil samples from five areas in Zambia were examined for the presence of genus Clostridium. Direct immunofluorescent assay (IFA) examination showed that C. septicum, C. novyi and C. chauvoei were detected in the soil of specific areas in Zambia, respectively. Causal organisms such as C. perfringens were isolated from the soil samples. The information of area-specific distribution of Clositridium species may give an efficient program in protecting cattle and man.

Shopping for sexually transmitted disease treatment: Focus group discussions among lay persons in rural and urban Zambia

Abstract: The aim was to gain insights into the rationale behind the selection of treatment sources by investigating perceptions of sexually transmitted diseases (STDs) and by identifying STD treatment sources used. Focus group discussions were held with 57 men and 44 women in one urban and one rural area in Zambia between May 1997 and June 1997. The focus group discussions were audiotaped and analyzed qualitatively. Participants combined traditional and modern treatment. The main reason given was that even when biomedical medicine was effective STDs could only be totally cured if the patient was cleansed by traditional herbs. Factors influencing health-seeking behavior were the persons perception how the diagnosis was determined type and cost of treatment demand for sexual partners and attitudes of health workers parents and the church. Barriers and enabling factors for the use of treatment sources were identified. Interventions to improve services and cooperation between the health sectors need to consider these factors. (authors)

First reports of soilborne wheat mosaic virus and wheat spindle streak mosaic virus in Africa.

Abstract: During 1997 and 1998, virus symptoms similar to those of Soilborne wheat mosaic virus (SBWMV) and Wheat spindle streak mosaic virus (WSSMV) were observed on nine wheat cultivars (Triticum aestivum cvs. Deka, Gamtoos, Lorie II, MM2, Nata, Nkwazi, P7, Scepter, and Scan) in the Central, Copper-Belt, Lusaka, and Southern provinces of Zambia. Symptoms were observed between June and August on wheat, which in Zambia is an irrigated crop grown during the cooler months (May to August). In fields suspected to be infected with SBWMV, irregularly distributed, circular patches of severely stunted sparse plants were observed. Because of these symptoms, the syndrome is described in Zambia as the “crater disease.” Infection was more common on light to medium sandy-loam clay soils, and affected patches were particularly common along the field edges and in poorly drained areas. Such waterlogged conditions are conducive to the multiplication and spread of Polymyxa graminis, the protist vector of SBWMV (1). Affected plants i...

Policy and strategy options for small‐scale mining development in Zambia

Abstract: Increasing populations compounded by limited formal sector employment have made small‐scale mining an important economic livelihood option for thousands of people in developing countries. Low barriers to entry, the principal economic characteristic of the sub‐sector, will ensure that small mining operations will continue to provide a livelihood for numerous unskilled workers in rural areas, where few alternative job opportunities exist. In addition, with correct policies and strategies in place, the sector has the potential to generate more employment and foreign exchange earnings. The successful evolution of small‐scale mining requires an enabling policy environment that recognizes its specific needs. In this paper small‐scale mining in Zambia is discussed by tracing the impact of changing policies on this sector.

Predominance of one T-cell antigen receptor BV haplotype in African populations.

Abstract: The human T-cell antigen receptor (TCR) is the counter-receptor for the HLA/peptide complex displayed on the surface of antigen-presenting cells. It confers antigen specificity on T lymphocytes and therefore plays a central role in pathogen recognition and host response. The most frequently used form of the TCR is a heterodimer composed of variable alpha and beta chains. We investigated allele frequencies for four variable-region gene segments of the beta chain (2S1, 3S1, 8S3, and 15S1) in 146 Caucasians and 165 Africans. The results reveal significant unexpected differences between the two populations for allele frequencies, phenotypes, genotypes, and haplotypes. Among Caucasians, there are 43 phenotypes, whereas there are 31 among the Africans studied. There are 17 haplotypes in the Caucasian sample but only 10 in Africans. This loss of diversity is largely due to the high frequency of one haplotype in the African sample which represents 65% of the informative chromosomes. At least one copy of this haplotype is present in 90% of informative individuals. As a result, 29% of Africans are homozygous for the common haplotype. Less genetic diversity at TCRBV is unexpected, since Africans usually show greater genetic diversity than other ethnic groups. For example, there are approximately twice as many HLA haplotypes in Africans compared to Caucasians. Homozygosity is also unexpected because it reduces the number of TCR variants available to recognize HLA pathogen-derived peptide complexes.

Water Law, Water Rights and Water Supply in Zambia – Issues and Perspectives

Abstract: Over the past two decades, a number of international declarations have sought to ensure access to safe water and sanitation for the majority (or all) of the world’s people. Despite these declarations, however, the reality is that clean water and safe waste disposal remains a life and death problem in much of the world – that in the 21 century. Zambia’s population stands at over 9 million with a high urbanisation rate resulting in over 50% of the population living in urban and periurban areas. Zambia’s population with access to safe drinking water is estimated at 43% and the corresponding figure for sanitation is 23%. This is so despite commendable investment programmes being implemented with the support of donor agencies during and after the International Drinking Water Supply and Sanitation Decade (IDWSSD). One of the major lessons has been that solutions to community water supply and sanitation should be sought less in technology and products and more in social, institutional and financial domains. In other words, more in the “software” domain. Unfortunately, even in this new awakening, water laws and water rights issues have so far been considered peripheral. For example, extremely rarely is an individual’s basic right to an adequate water supply enshrined in national law. The paper attempts to identify (and promote awareness and understanding of), the constraints and enabling conditions provided by existing water laws (statutory and customary) with regard to the poor having access to, or being entitled to, a safe and reliable supply of water and sanitation. The paper examines Zambia’s water policy, laws and rights regimes as they relate to water supply and sanitation provision for the poor while at the same time putting into perspective the current debate surrounding economic, social and cultural rights vis-a-vis political and civil rights. It is concluded that there are more constraints than enabling conditions provided to domestic water supply and sanitation (provision and access) for rural/urban poor by written and unwritten local/national laws and water rights (and related) issues in Zambia.

Demonstration of botulinum toxins of types B and D in soil samples from Zambia.

Abstract: (2000). Demonstration of botulinum toxins of types B and D in soil samples from Zambia. Annals of Tropical Medicine & Parasitology: Vol. 94, No. 4, pp. 409-411.

Performance of some apple cultivars under tropical Zambian conditions.

Abstract: SummaryTen apple cultivars (Malus domestica Bork) Ein Shemer, Anna, Rome Beauty, Tropical Beauty, Alexander, Orleans, Winter Banana, Black John, Starking Delicious and Red Delicious were evaluated for their suitability for tropical Zambian conditions. Winter Banana, Black John, Starking Delicious and Red Delicious, which were mostly high-chill cultivars, showed poor vegetative development: delayed budbreak, shoot growth and progressive loss of vigour and most of the trees died before maturity. Of the remaining low-chill cultivars, ‘Ein Shemer’ had the highest fruit yield at 49 6 2.3 kg tree21 and ‘Alexander’ the lowest (5.3 6 1.0 kg tree21). This response was due to the high number of fruits per tree, ‘Ein Shemer’ had up to 907 6 83.7 per tree whereas low yielding cultivars like ‘Rome Beauty’ and ‘Tropical Beauty’ had fewer than 106 6 25.3 fruits per tree. The individual fruit weight was inversely related to the total number of fruits per tree. It ranged from 58 6 5.1 g in Ein Shemer to 191 6 24.8 g in ‘R...

Ultrasonographic findings of an ovarian abscess in a cow.

Abstract: Ultrasonographic examination was carried out in a cow with an ovarian abscess. Real time ultrasound scanning using a 7.5 MHz linear probe per rectum revealed an active left ovary with follicles of up to 11 mm in diameter and an enlarged right ovary measuring 6 x 6 cm, with a mass of 4 x 3 cm. The mass had varied echotexture, a thick hyperechoic boundary and a hypoechoic centre with echoic foci. It was tentatively diagnosed as an ovarian tumour or abscess. After ovariectomy, grossly the right ovary measured 6 x 6 x 5 cm and on cutting cheesy pus oozed out. The abscess was completely localised within the ovary, 4 cm in diameter and encapsulated thickly. On bacteriological examination Staphylococcus spp. was isolated. This is a rare case of ovarian abscess.

Derivation of Standard Treatment of Spin Addition From Probability Amplitudes

Abstract: In a recent paper, we introduced a new way of treating systems of compounded angular momentum. We obtained the probability amplitudes for measurements on the systems and used these to derive the matrix treatment of compounded spin. However, the matrix forms are in 3- and 4- dimensional space and are therefore entirely different from the standard forms. This raises the question of the connection between these forms and the standard forms. In this paper, we answer this question. We not only derive the standard matrix treatment of spin addition - we discover a more generalized form of the theory. We apply the new generalized theory to the singlet and triplet states arising from the addition of the spins of two systems of spin 1/2 each. We obtain new generalized forms of the vectors and operators for these cases, and show that they reduce to the standard forms in the appropriate limit.

Corn genotypes show distinctive growth responses to various herbicides.

Abstract: Corn (Zea mays L.) inbreds and hybrids may respond differently to specific herbicides. Screening corn inbreds and hybrids for tolerance to herbicides is essential as this will enable producers to reduce the risk of crop injury by applying appropriate herbicides. A study was conducted to determine the tolerance of corn to herbicides and to compare results in the greenhouse and in the field. Both inbreds and hybrids demonstrated significant differences in their response to herbicides. Hybrids were generally more tolerant than inbreds. Of the herbicides, metazachlor was the most injurious to corn genotypes. Differential recovery from herbicide injury was observed in the field, and some genotypes recovered fully during the growing season while others did not. Some genotypes showed significant reductions in shoot dry mass while their root dry mass was not reduced; the opposite effect was also noted for certain genotype/herbicide combinations. Percentage reduction in grain yield in the field was positi...