Los gemelos en las religiones tradicionales africanas.

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Correlating standard penetration test and dynamic probe super heavy penetration resistance values in sandy soils

This paper presents a statistical method used to develop an empirical equivalence between the Standard Penetration Test (SPT) and the Dynamic Probe Super Heavy (DPSH) in sandy material. Penetration resistance values from the two tests are often taken as equivalent for design purposes, as the same drive energy is used in both. SPT and DPSH resistance values from different geological depositional and weathering environments were examined. The data came from the following areas across southern Africa: Matola in Mozambique, Gope in Botswana, Umdloti and Cape Town in South Africa, and Illha de Luanda in Angola. It was apparent that energy losses were greater in the DPSH test than in the SPT, leading to higher resistance values in the former. The SPT is carried out within a borehole, whereas the DPSH is continuously driven into the soil. The dynamic force applied to the DPSH rods causes soil to fill the small air annulus around the rods, exerting a frictional resistance. The different geological settings of the test sites revealed that, although different factors cause the friction, the equivalence varied in a similar manner. Hence a single correlation formula is suggested to determine equivalent SPT values from raw DPSH resistance values

Remediation of heavy metal contaminated fine grained soils using electrokinetic geosynthetics

Among the most promising novel methods for treating heavy metal contamination in fine soils is electrokinetic soil remediation - passing a low-voltage current through the soil that causes the target contaminants to migrate to the electrodes where they can be captured, broken down or immobilized. However, the widespread in-situ application of this process as a creative solution for the problem of metal contamination has been prevented because of a variety of problems, some of which are linked to the available electrodes. The limitations related to the available electrodes include: corrosion of the anodes difficulties in removing contaminated water and gases from the electrodes poor electrical contact of electrodes with the soil, cost of producing functioning electrodes, and limitations related to the physical form of the electrodes. Many of these historical limitations have been eliminated by the introduction of Electrokinetic Geosynthetics (EKGs) which combine electrokinetics with geosynthetics technology to create geosynthetice lectrodes. In this investigation, the use of an EKG system to capture and dispose of zinc ions from kaolin soil is evaluated by conducting extensive labor4tOry tests using specially designed bench scale tanks. A comprehensive test programme was established to include two electrokinetic remediation removal approaches: One Process Approach and Two Process Approach. The former was achieved by electro, migration of metal contaminants towards the cathode electrode without any external enhancement agent while the latter combined soil flushing with the electrokinetic process. The testing technique enabled the study of effects of. water flushing, soil depth, intermittent currents and replenishing draining chambers along the soil profile with deionised water, on the efficiency of cation removal. The respective responses were primarily presented in terms of electrical current/test duration, water content/test duration, zinc concentration/normalised distance from the anode, zinc concentration/ test duration and pW normalised distance from the anode. Results indicated that the EKG system has a lot of potential for cleaning up soil at sites contaminated by heavy metals and other harmful compounds. The in-depth analysis also showed clearly that combining the technique with soil flushing improved the effectiveness of the treatment operation. The study considerably extended the understandinogf the performance of electrokinetic technology particularly in fine grained soil and are as where further research would improve this understanding were highlighted.EThOS - Electronic Theses Online ServiceCommonwealth Scholarship and Fellowship PlanGBUnited Kingdo

Using shredded plastic shopping bags wastes in soil Improvement

Colossal tonnages of waste are produced each year worldwide, with a considerable amount being in the form of plastic (polyethylene) grocery bags. Most of this is non-degradable and destined for landfill. This study investigated the potential of utilising this type of waste to reinforce soils paving way for its use in civil engineering projects such as in road bases, embankments and structure foundations. A comprehensive test programme was undertaken including direct shear tests on two selected sandy soils. Plastic strips were used as reinforcement inclusions at concentrations of up to 0.3% by weight. The effect of the dimensions of the strip was investigated by varying the length of the strips from 15 to 45 mm and the width from 6 to 18 mm. Shear strength parameters were obtained for each composite material from which analyses were done to identify the extent of the soil improvement. The laboratory experiments favourably suggest that inclusion of these strips in sandy soils would be an effective soil reinforcement method

Effects of mixture of grinding media of different shapes on milling kinetics

This dissertation focuses on the determination of breakage parameters in order to describe the performances of mixtures of grinding media of different shapes. A series of batch grinding tests were carried out using the same mass of spherical balls, EclipsoidsTM and cubes to break coarse, medium and fine sizes of quartz material. Then, mixtures of the same mass made of spherical balls and cubes, spherical balls and EclipsoidsTM were successively considered. The breakage parameters were determined and used to evaluate the grinding performances of the mixtures of grinding media. It was found that mixtures of grinding media shapes can increase the breakage rate in a particular milling environment. But, spherical balls remain the most efficient grinding media. Finally, an optimal mixture made of grinding media of different shapes cheaper to manufacture can be used in the grinding process alternatively to 100 % balls

Improving the quality and relevance of environmental learning through the use of a wider range of preferred teaching methods: a case of primary schools in Mufulira District in the Copperbelt Province in Zambia

The study was conducted to investigate whether the use of a wider range of teaching methods can improve the quality of environmental learning in five Zambian primary schools. Nine teachers from five schools were involved in the preliminary stage of answering of questionnaires, interviews and focus group discussions about the use of dominant teaching methods and new teaching methods; while only four were involved in the observations of four lessons. The study is a contribution to the on‐going debate on the investigation of whether teaching methods used by teachers can be one of the factors that can influence the quality of education. Definitions of quality and educational quality in particular, are not easy to establish and no agreed upon framework for educational quality exists at present. This study reviews the debates on educational quality, and identifies three major paradigms or discourses on educational quality; and considers the human rights, social justice and capabilities approaches and educational quality frameworks as being relevant to environmental learning and education for sustainable development in the Southern African Development Community context. This, together with a review of research on teaching methods in environmental education, provides the theoretical framework for this study. Using action research and an interpretative methodological framework, a series of research activities were undertaken to generate research data because the study was investigating the teachers’ practice with a view to probe change and to analyse the findings. Nine teachers participated in the preliminary stage of answering questionnaires and focus group interviews reflecting on existing teaching methods. In stage two of this study, teachers went through a planning workshop during which they planned lessons using new preferred teaching methods. The third stage was lesson observations of planned lessons. The final stage was the reflection workshop during which the teachers shared their experiences with the use of new teaching methods. The teaching practices of teachers using the new teaching methods were the subject of further analysis. In order to find out how the use of a wide range of teaching methods can improve quality of environmental learning in primary schools nine teachers were observed teaching lessons with new teaching methods. The Nikel and Lowe (2010) fabric of dimensions of educational quality was adapted and used to find out if teachers included dimensions of quality in the teaching process. Additional socio‐cultural and structural quality dimensions, identified through a review of southern African research, were used to find out if teachers included contextualized regional dimensions of educational quality. This was done to investigate whether the process of teaching and learning was relevant to the learners. Teachers involved in the research reflected that when they used a wider range of teaching methods the result was that the learning opportunities for learners were enhanced and that the methods added value to their teaching, improving the quality of their teaching. The use of a wider range of teaching methods showed the presence of several indicators of dimensions of educational quality, as reflected in the quality analysis tool. Teachers indicated that the use of a wider range of teaching methods led them to include the socio‐cultural dimensions such as the use of local languages and structural dimensions such as informal seating arrangements or group work that they would otherwise neglect if they used the traditional narrow range of teaching methods. A wider range of teaching methods provided learners with an enjoyable learning atmosphere during the lesson. The research also identified that this study can be taken further through broader observations, and that the educational quality dimensions tool is useful for different levels of the education system, and that it has potentially productive uses in teacher education, particularly for observations during teaching practice

Effect of seed generation, rhizobia inoculation and plant density on productivity and seed quality of soybean [Glycine max (l.) Merril] and groundnut [Arachis hypogea (l.)] In Dedza and Machinga districts of Malawi

Two on-farm, researcher designed-farmer managed trials were arranged in split-plot in a randomised complete block design (RCBD) with seed generation as main plot factor while inoculation and plant density were subplot factors for soybean and groundnut trials, respectively, in Dedza and Machinga districts in the 2017/2018 season. Following the field trials, Screen house experiments were conducted at Bunda College, Crop and Soil Sciences Students research farm to evaluate the effect of mother environment on seed quality of soybean and groundnut. This study was laid out in a completely randomised design (CRD). The overall objective of these trials was to investigate effects of seed generation, inoculation, plant density and mother environment on soybean and groundnut productivity and seed quality. In Machinga, response to inoculation for BNF and grain yield of soybean was 67 % (p=0.002) and 27 % (p=0.016) higher in recycled than certified seed, respectively. In Dedza inoculation of soybean significantly increased BNF by 74 % (p=0.004) and grain yield by 21 % (p=0.029), while planting certified soybean increased grain yield by 18 % (p=0.031). In Dedza, planting recycled seed significantly increased BNF by 21.4 % (p=0.011) and grain yield by 24.2 % (p=0.041) while planting groundnut in twin rows increased BNF by 38.5 % (p=0.004) and grain yield by 145.8 % (p<0.001), respectively. In Machinga, planting groundnut in twin rows increased BNF by 32.5 % (p=0.025) and grain yield by 87 % (p<0.001). Because of poor germination for certified groundnut seed, a covariate analysis controlling for plant density revealed that use of certified seed increased BNF and yield of groundnut (p<0.001). Results of screen house experiments showed that mother environment significantly affected seed quality for both soybean and groundnut indicating that seed production site is an important element for production of quality seed

MAKING A CASE ON SOCIAL INTERACTION OF PARENTS OF CHILDREN WITH AUTISTIC SPECTRUM DISORDERS: A STUDY OF SELECTED COMPOUNDS OF LUSAKA, ZAMBIA

Parenting a child is a challenging experience let alone parenting a child with a disability. The nature of the disability in a child goes with its complexity and it often puts parenting skills to the test. This study explores the experiences on social interactions of parents with Autistic Spectrum Disorder (ASD) in selected compounds of Lusaka, Zambia. The study used an interpretative phenomenological framework supported by qualitative approach. In-depth interviews were used to collect data. Non-probability criterion purposive sampling procedure was used to select participants. The sample size comprised of 10 parents with children with ASD. Qualitative data was analyzed thematically. The study revealed that parents had unique experiences in raising their children with ASD. These included; inadequate information on ASD; lack of support services; miscommunications between parents and children with ASD; stigmatization; lack of adequate sleeping time and negative attitude towards parents and their children with ASD. It was evident from the study that parents require supportive services including counselling to enable them to deal with the complexities that emanate from parenting children with ASD. In view of these the study recommended increased awareness on ASD; development, promotion and regular evaluation of intervention strategies parents use aimed at improving the daily lives of parents and their children with ASD in the study sites.  Article visualizations

Eff ect of daily iron supplementation on health in children aged 4–23 months: a systematic review and meta-analysis of randomised controlled trials

Background About 47% of preschool children worldwide are anaemic. Daily oral iron supplementation is a commonly recommended intervention for treatment and prevention of anaemia, but the effi cacy and safety of iron supplementation programmes is debated. Thus, we systematically reviewed the evidence for benefi t and safety of daily iron supplementation in children aged 4–23 months. Methods We searched Scopus and Medline, from inception to Feb 5, 2013, WHO databases, theses repositories, grey literature, and references. Randomised controlled trials that assigned children 4–23 months of age to daily oral iron supplementation versus control were eligible. We calculated mean diff erence (MD) or standard MD (SMD) for continuous variables, risk ratios for dichotomous data, and rate ratios for rates. We quantifi ed heterogeneity with the I2 test and synthesised all data with a random-eff ects model. This review is registered with the International Prospective Register of Systematic Reviews, number CRD42011001208. Findings Of 9533 citations identifi ed by the search strategy, 49 articles from 35 studies were eligible; these trials included 42 306 children. Only nine studies were judged to be at low risk of bias. In children receiving iron supplements, the risk ratio for anaemia was 0·61 (95% CI 0·50–0·74; 17 studies, n=4825), for iron defi ciency was 0·30 (0·15–0·60; nine studies, n=2464), and for iron defi ciency anaemia was 0·14 (0·10–0·22; six studies, n=2145). We identifi ed no evidence of diff erence in mental (MD 1·65, 95% CI –0·63 to 3·94; six studies, n=1093) or psychomotor development (1·05, –1·36 to 3·46; six studies, n=1086). We noted no signifi cant diff erences in fi nal length or length-for-age, or fi nal weight or weight-for-age. Children randomised to iron had slightly lesser length (SMD –0·83, –1·53 to –0·12; eight studies, n=868) and weight gain (–1·12, –1·19 to –0·33) over the course of the studies. Vomiting (risk ratio 1·38, 95% CI 1·10–1·73) and fever (1·16, 1·02–1·31) were more prevalent in children receiving iron. Interpretation In children aged 4–23 months, daily iron supplementation eff ectively reduces anaemia. However, the adverse eff ect profi le of iron supplements and eff ects on development and growth are uncertain. Adequately powered trials are needed to establish the non-haematological benefi ts and risks from iron supplementation in this group