Class frequency distribution for a surface raw water quality index in the Vaal Basin

A harmonised in-stream water quality guideline was constructed to develop a water quality index for the Upper and Middle Vaal Water Management Areas, in the Vaal basin of South Africa. The study area consisted of 12 water quality monitoring points; V1, S1, B1, S4, K9, T1, R2, L1, V7, V9, V12, and V17. These points are part of a Water Board’s extensive catchment monitoring network but were re-labelled for this paper. The harmonised guideline was made up of 5 classes for NH4+, Cl-, EC, DO, pH, F-, NO3-, PO43- and SO42- against in-stream water quality objectives for ideal catchment background limits. Ideal catchment background values for Vaal Dam sub-catchment represented Class 1 (best quality water), while those for Vaal Barrage, Blesbok/Suikerbosrand Rivers and Klip River represented Classes 2, 3 and 4, respectively. Values above those of Klip River ideal catchment background represented Class 5. For each monitoring point, secondary raw data for the 9 parameters were cubic-interpolated to 2 526 days from 1 January 2003 to 30 November 2009 (7 years). The IF-THEN-ELSE function then sub-classified the data from 1 to 5 while the daily index was calculated as a median of that day’s sub-classes. Histograms were constructed in order to distribute the indices among the 5 classes of the harmonised guideline. Points V1 and S1 were ranked as best quality water (Class 1), with percentage class frequencies of 91% and 60%, respectively. L1 ranked Class 3 (34%) while V7 (54%), V9 (53%), V12 (66%) and V17 (46%) ranked poorly as Class 4. B1 (76%), S4 (53%), K9 (41%), T1 (53%) and R2 (61%) ranked as worst quality (Class 5). The harmonised in-stream water quality guideline resulted in class frequency distributions. The surface raw water quality index system managed to compare quality variation among the 12 points which were located in different sub-catchments of the study area. These results provided a basis to trade pollution among upstream-downstream users, over a timeframe of 7 years. Models could consequently be developed to reflect, for example, quality-sensitive differential tariffs, among other index uses. The indices could also be incorporated into potable water treatment cost models in order for the costs to reflect raw water quality variability.Keywords: class frequency distribution; cubic interpolation; harmonised in-stream water quality guideline; ideal catchment background; Vaal basin; water quality inde

A More Efficient Way Of Obtaining A Unique Median Estimate For Circular Data

The procedure for computing the sample circular median occasionally leads to a non-unique estimate of the population circular median, since there can sometimes be two or more diameters that divide data equally and have the same circular mean deviation. A modification in the computation of the sample median is suggested, which not only eliminates this non-uniqueness problem, but is computationally easier and faster to work with than the existing alternative

Effect Of Position Of An Outlier On The Influence Curve Of The Measures Of Preferred Direction For Circular Data

Circular or angular data occur in many fields of applied statistics. A common problem of interest in circular data is estimating a preferred direction and its corresponding distribution. It is complicated by the wrap-around effect on the circle, which exists because there is no natural minimum or maximum. The usual statistics employed for linear data are inappropriate for directional data, as they do not account for its circular nature. The robustness of the three common choices for summarizing the preferred direction (the sample circular mean, sample circular median and a circular analog of the Hodges-Lehmann estimator) are evaluated via their influence functions

Effect of wheat bran supplementation with fresh and composted agricultural wastes on the growth of Kenyan native wood ear mushrooms [Auricularia auricula (L. ex Hook.) Underw.]

Nutrient supplements and agricultural wastes used for mushroom cultivation are important in improving establishment and production of mushrooms. Agricultural wastes such as sawdust, grass, sugarcane bagasse, wheat straw and maize cobs have successfully been used for the production of Kenyan wood ear mushrooms [Auricularia auricula (L. ex Hook.) Underw.]. However, the effect of varying concentrations of wheat bran supplements on their productivity has not been fully researched. In this study, fresh and composted agricultural wastes were supplemented with wheat bran at concentrations of 0, 5, 10 and 20%. The cultivation experiment was arranged in a completely randomized design (CRD) and replicated three times. Data was collected on days to spawn run, days to primordial initiation, primordial concentration quality and biological efficiency. The data collected was subjected to analysis of variance using SAS version 9.1. Mean separation was done using least significant difference (LSD) and effects were declared significant at 5% level. Key words: Wood ear mushrooms, fresh and composted agricultural wastes, wheat bran, Kenya

Assessment of knowledge, attitudes and practices of infant feeding in the context of HIV: A case study from western Kenya

Guidelines for infant feeding options among HIV-positive mothers are changing with informative research. Cultural factors, socialisation processes, gender dimensions and socio-economic status within communities should be considered in recommending feasible and sustainable options. The objective of this study was to assess the knowledge, attitudes and practices with regards to infant feeding in the context of HIV. A cross-sectional study was conducted between November 2003 and January 2004. The study was carried out in Kosirai Division, Nandi-North District, in western Kenya. The target population was community members aged 18 - 45 years and key informants aged 18 years and above. Structured questionnaires and in-depth interviews were used to collect data. Multistage and snowball sampling methods were used to identify study participants. Quantitative data were analysed using the SPSS statistical package for social scientists (Version 12). Cross-tabulations were calculated and Pearson’s chi-square test used to test significance of relationships between categorical variables. Recorded qualitative data were transcribed and coded. Themes were developed and integrated. A generation of concepts was used to organise the presentation into summaries, interpretations and text. A total of 385 individuals participated in the survey, 50% of whom were women. There were 30 key informants. Farming was the main source of income but half of the women (49.7%) had no income. Most of the respondents (85.5%) knew of breastfeeding as a route of HIV transmission with sex (p=0.003) and age (p=0.000) being highly associated with this knowledge. Breastfeeding wasthe norm although exclusive breastfeeding was not practised. Cow’s milk, the main breast milk substitute, was reported as being given to infants as early as two weeks. It was the most popular (93.5%) infant feeding option in the context of HIV/AIDS. Heating expressed milk, wet nursing and milk banks were least preferred. Thus, the social, cultural and psychological complexity of infant feeding practices should be taken into account when advocating appropriate infant feeding options. Further research is required to determine the safety of using cow’s milk as an infant feeding option. Community engagement, including education and awareness strategies, specific to the benefits of exclusive breastfeeding as a mechanism to reduce the risk of HIV transmission is urgently needed

Access to Water among Slum Dwellers in Nakuru Town, Kenya: Lessons from Kaptembwa Location

Majority of urban residents in sub-Saharan Africa live in slums often characterised by lack of basic services such as water and sewerage.  With increasing pressures due to population growth, aging infrastructure, climate change, coupled with an unsustainable conventional water management, cities and urban areas in sub-Saharan African countries are facing enormous difficulties and will experience huge challenges in future in efficiently managing the scarce and increasingly unreliable water resources. This paper examines the level of access to water among slum dwellers in Nakuru town, Kaptembwo location, Kenya. The guiding questions the paper addresses are: (1) What is the level of households’ access to water? and (2) Has NAWASSCO met the demand for water by residents? A descriptive survey design was used and structured questionnaire administered to 280 households to collect the requisite data. Data was analyzed using descriptive statistical techniques and statistical software (SPSS) version 20. Results show that only 65.6% of the basic water requirements of the residents are met and that only 25% of the households access the minimum recommended 50 l/c/d. The low levels of investment in water infrastructure is the major explanatory reason for reduced access to water services. The paper shows that the domestic water supply in Kaptembwo is quite low according to the international standards. This situation is attributed to poor and inefficient water distribution system, unreliable and irrational rationing system, and poor management of water delivery services by NAWASSCO. This paper thus recommends that NAWASSCO should improve its distribution network and related infrastructure in order to facilitate adequate and reliable water provision to the study area. Other strategies including roof-harvesting and collection of run-off water if properly planned and managed could increase the water supply situation in the study area. Keywords: Access, water services, water supply, slums, household, water infrastructur

Successful pregnancy outcome following laparoscopic myomectomy: case report

Laparoscopic myomectomy is now widely used as an alternative to laparotomy in the management of symptomatic uterine fibroids. The advantages of this minimal access approach outweigh those of the open techniques. The pregnancy outcomes between the two methods have been studied and are comparable, but there still exists a lot of scepticism locally concerning this. It is against this background that we present a 31 year old nulliparous lady who had a two year history of primary infertility secondary to multiple uterine fibroids, the largest being fundal and measuring 6.6cm. She underwent a successful laparoscopic myomectomy in November, 2006 and conceived spontaneously in February 2007. Her antenatal follow up was uneventful. She delivered a live male, 2,650 grams by Caesarean section in October, 2007 and had an unremarkable peuperium. With the availability of proper equipment, instruments, and adequately developing skills, laparoscopic myomectomy is feasible locally and with proper patient selection could result in favourable outcome as it is elsewhere

Effect of mother’s migration on under-two mortality in Kenya

This study examines the effect of mothers’ migration status controlling for other proximate factors (socio-economic, environmental and bio-demographic characteristics) on under two mortality in Kenya. Data used were drawn from 2003 Kenya Demographic Health Survey with focus on infants and children below two years in age. A total of 5949 infants and children born five years before the survey are used in the analysis. Cox proportional hazard model is used to assess the relative effect of the migration status (migrant or non-migrant) of the mother on survival rates controlling for other explanatory variables. The general results shows that children of migrant mothers especially those of urban-rural migrants face a higher mortality risk compared to those of non-migrant mothers. The results show that failure to account for migration may alter the estimation of urban-rural differentials in childhood mortality

Access and benefit-sharing policies for climate-resilient seed systems.

The synthesis report is part of a series of papers on Integrated Seed Sector Development (ISSD) in Africa’s thematic working group on Matching national realities with global commitments. The thematic working group addressed the main question on how African governments implement their global commitments while fostering a viable pluralistic sector. The main hypothesis was that making these commitments more coherent with the practices and realities of farmers and creating an enabling environment for strengthening multiple seed systems will increase farmers’ access to quality seed. Three main topics were discussed under this theme: access and benefit sharing for climate resilient seed systems; national and regional seed laws that support the development of a robust, integrated seed sector that supports smallholder farmers' needs; and creating room for informal and intermediary seed systems in a UPOV '91 informed Plant Variety Protection system. This study provides an overview of climate related changes in past, present and future and the challenges to access to and exchange of genetic resources for climate change adaptation through different access and benefit sharing regimes in 4 countries – Zambia, Zimbabwe, Rwanda and Uganda. Findings from the studies indicate that most African countries face challenges in accessing required PGR for climate change adaptation because they do not have online accession-level documentation; they have not fully implemented international commitments related to ABS and national and regional seed laws hamper the flow of seeds and genetic resources. As a way forward the paper proposes capacity development for mutually supportive implementation of the ITPGRFA, Nagoya protocol and seed laws in ways which reflect the reality and diversity of different seed systems

Access and benefit sharing policies for climate resilient seed systems: matching global commitments with national realities.

This synthesis paper provides a summary of main findings on climate resilient seed systems and access and benefit sharing of case studies from Uganda, Rwanda, Zambia and Zimbabwe. This study analyses what is actually happening at the national and subnational levels in terms of climate change, its impacts on particular crops, what experiences countries have had to date in terms of accessing, using and sharing benefits derived from genetic resources for climate change adaptation, and what kinds of ABS policy initiatives or reforms could help those countries to make better use of genetic diversity for climate change adaptation in the future. This study is designed to analyze how these different ‘threads’ come together at national and subnational level in the four countries. Findings from these studies indicate that countries are already facing climate change which is affecting farmers and shaping their needs in terms of suitably adapted seed. As a result, the countries are embracing (inter and intra specific) crop diversification as a means to adapt to climate changes. This depends upon accessibility, availability and use of inter and intra specific crop genetic diversity from local, national and international sources. The proportion of PGRFA in the countries’ national genebanks that is potentially adaptable to that country’s changing climate is decreasing over time (as climates change more). National level research and the development of new varieties is also not sufficient to meet these demands. Countries are therefore becoming more interdependent. There are also significant constraints on ability to access, use and share benefits associated with materials in other countries as a result of the lack of on-line accession level documentation (and linked implementation of ITPGRFA and Nagoya Protocol) and lack of proper polices, legislation and guidelines on ABS. The study therefore recommends that international partnerships and programmes are important mechanisms for the exchanges of genetic resources into and out of the four countries for agricultural research and development especially at regional level and that the ITPGRFA and Nagoya Protocol are not self-executing agreements but need to be proactively implemented. In addition, considerable investment in capacity building is necessary for stakeholders – including farmers – to be able to exchange genetic resources in a way that makes seed systems more resilient