A column generation approach to a carpentry cutting stock problem: a case study for planks cutting in Zimbabwe

The carpentry sector like any other industry is faced with a cutting stock problem to minimize incurred waste. The main purpose of this project was to develop a mathematical model which will solve the cutting stock problem using column generation approach for Ashtons Company in Chinhoyi. The interview method was used to collect data relating to the cutting stock problem. The column generation approach of iterative computational routines was used because it develops successively better solutions until an optimal solution is obtained. The results revealed that the method is an appropriate method in solving business problems, that is, how many boards should be cut to meet demand with minimum incurred waste. A user friendly graphical user interface was developed using Visual Basic programming which could be used by the carpentry manager.Keywords: cutting stock problem, feasible solution, optimal solution, integer programmingAfrican Journal of Educational Studies in Mathematics and Sciences Vol. 9, 201

An Experimental Evaluation of Position Estimation Methods for Person Localization in Wireless Sensor Networks

In this paper, the localization of persons by means of a Wireless Sensor Network (WSN) is considered. Persons carry on-body sensor nodes and move within a WSN. The location of each person is calculated on this node and communicated through the network to a central data sink for visualization. Applications of such a system could be found in mass casualty events, firefighter scenarios, hospitals or retirement homes for example. For the location estimation on the sensor node, three derivatives of the Kalman Filter and a closed-form solution (CFS) are applied, compared, and evaluated in a real-world scenario. A prototype 65-node ZigBee WSN is implemented and data are collected in in- and outdoor environments with differently positioned on-body nodes. The described estimators are then evaluated off-line on the experimentally collected data. The goal of this paper is to present a comprehensive real-world evaluation of methods for person localization in a WSN based on received signal strength (RSS) range measurements. It is concluded that person localization in in- and outdoor environments is possible under the considered conditions with the considered filters. The compared methods allow for suffciently accurate localization results and are robust against inaccurate range measurements

Taking up the cudgels against gay rights? Trends and trajectories in African Christian theologies on homosexuality

Against the background of the HIV epidemic and the intense public controversy on homosexuality in African societies, this article investigates the discourses of academic African Christian theologians on homosexuality. Distinguishing some major strands in African theology, that is, inculturation, liberation, women’s and reconstruction theology, the article examines how the central concepts of culture, liberation, justice, and human rights function in these discourses. On the basis of a qualitative analysis of a large number of publications, the article shows that stances of African theologians are varying from silence and rejection to acceptance. Although many African theologians have taken up the cudgels against gay rights, some “dissident voices” break the taboo and develop more inclusive concepts of African identity and African Christianity

The University of Zimbabwe College of Health Sciences (UZ-CHS) BIRTH COHORT study: rationale, design and methods

Background: Commencing lifelong antiretroviral therapy (ART) immediately following HIV diagnosis (Option B+), has greatly improved maternal-infant health. Thus, large and increasing numbers of HIV-infected women are on ART during pregnancy, a situation concurrently increasing numbers of HIV-exposed-uninfected (HEU) infants. Compared to their HIV-unexposed-uninfected (HUU) counterparts, HEU infants show higher rates of adverse birth outcomes, mortality, infectious/non-communicable diseases including impaired growth and neurocognitive development. There is an urgent need to understand the impact of HIV and early life ART exposures, immune-metabolic dysregulation, comorbidities and environmental confounders on adverse paediatric outcomes. Methods: Six hundred (600) HIV-infected and 600 HIV-uninfected pregnant women ≥20 weeks of gestation will be enrolled from four primary health centres in high density residential areas of Harare. Participants will be followed up as mother-infant-pairs at delivery, week(s) 1, 6, 10, 14, 24, 36, 48, 72 and 96 after birth. Clinical, socio-economic, nutritional and environmental data will be assessed for adverse birth outcomes, impaired growth, immune/neurodevelopment, vertical transmission of HIV, hepatitis-B/C viruses, cytomegalovirus and syphilis. Maternal urine, stool, plasma, cord blood, amniotic fluid, placenta and milk including infant plasma, dried blood spot and stool will be collected at enrolment and follow-up visits. The composite primary endpoint is stillbirth and infant mortality within the first two years of life in HEU versus HUU infants. Maternal mortality in HIV-infected versus -uninfected women is another primary outcome. Secondary endpoints include a range of maternal and infant outcomes. Sub-studies will address maternal stress and malnutrition, maternal-infant latent tuberculosis, Helicobacter pylori infections, immune-metabolomic dysregulation including gut, breast milk and amniotic fluid dysbiosis. Discussion: The University of Zimbabwe-College of Health-Sciences-Birth-Cohort study will provide a comprehensive assessment of risk factors and biomarkers for HEU infants’ adverse outcomes. This will ultimately help developing strategies to mitigate effects of maternal HIV, early-life ART exposures and comorbidities on infants’ mortality and morbidity. Trial registration: ClinicalTrial.gov Identifier: NCT04087239. Registered 12 September 2019

Behavioural characteristics of the scale insect aspidoproctus sp. near glaber (Homoptera: Margarodidae) in different instar stages in Miombo woodlands in Hurungwe, Zimbabwe

The behavioural characteristics of the different instar stages of Aspidoproctus sp. near glaber (Lindiger) were studied over a period of 10 months from December 1994 to October 1995 on Brachystegia boehimii and Julbernardia globiflora in the field in Hurungwe, Zimbabwe and on potted Afzelia quanzensis seedlings in the laboratory at the University of Zimbabwe. The behavioural aspects studied were egg-laying and hatching behaviour, crawler behaviour, settling behaviour, moulting behaviour, honey dew secretion, and over-wintering behaviour. Dissection of 20 randomly selected adult females daily for a period of 10 days during the oviposition period revealed that the scale insect produced eggs in batches and retained them inside the female body where incubation and eclosion took place. Dissection of 20 adult females when the insects were fully distended showed that the number of eggs produced per female ranged from 934 to 5673 (with a mean of 2403 ±1281 eggs). The newly emerged crawlers congregated around the fringes of the maternal scale before they started dispersing. Crawler emergence and congregation period were strongly affected by ambient temperature. The crawlers moved upwards until they reached the thinner twigs, petioles and leaves in the crown of the host plant where they wandered up and down before settling down to feed. The insect moulted three times and on each moult the insect actually escaped from the old exuvium leaving the latter attached to the host plant. After each moult the insect moved down to a thicker portion of the host plant. Throughout its development, the insect produced copious amounts of honeydew

Assessing the functionality of the department of the education in disruptive times using the Viable System Model: Case of the KwaZulu-Natal Department of Education, South Africa

Organisational functionality is critical for ensuring that the organisation remains focused on providing its performance mandate, especially in times of disruption such as the Corona Virus Pandemic, natural disasters caused by floods, earthquakes, and civil unrest. In times of disruption, organisation could enhance their functionality by applying the Viable System Model (VSM). The KwaZulu-Natal Department of Education (KZNDOE), experienced functionality-related challenges during the Pandemic which hindered the delivery of teaching and learning across most schools. Therefore, the study aimed to enhance the department's functionality using the VSM. The target population consisted of 300 senior managers, principals, and educators at the KZNDOE. The study employed an exploratory research design gathering data from 14 respondents through interviews as the data collection instrument. Data were analysed thematically using the NVivo 12 model. The study findings revealed that KZNDOE was not prepared to deal with the complexity presented by the Corona Virus Pandemic due to a dysfunctional structure, lack of resources, and skills incompetency to deal with complexity. To address the challenges, the department reviewed the functional structure which was last reviewed in 2011 to one that is adaptive in responding to the complex environment. The review would include the change of structure by creating new structures within the department that can deal with the Pandemic. For example, the study recommended a specific structure that deals with enhancing performance, Corona Virus Pandemic communication network, empowerment structures for educators, and structures to provide for remote learning and pre-learning materials. The study however recommended that a similar study could be conducted in other provinces to have a balanced view before making national inferences