A rescheduling heuristic for the single machine total tardiness problem

In this paper, we propose a rescheduling heuristic for scheduling N jobs on a single machine in order to minimise total tardiness. The heuristic is of the interchange type and constructs a schedule from the modified due date (MDD) schedule. Unlike most interchange heuristics that consider interchanges involving only two jobs at a time, the newly proposed heuristic uses interchanges that may involve more than two jobs at any one time. Experimental results show that the heuristic is effective at reducing total tardiness producing schedules that either similar or better than those produced by the MDD alone. Furthermore, when applied to some test problems the heuristic found optimal schedules to all of them

Role of Cytokines in Trypanosoma brucei-Induced Anaemia: A Review of the Literature

Background: Anaemia is an important complication of trypanosomiasis. The mechanisms through which trypanosomal infection leads to anaemia are poorly defined. A number of studies have implicated inflammatory cytokines, but these data are limited and inconsistent. In this article, we reviewed the published literature on cytokines associated with Trypanosoma brucei infections and their role in the immunopathology leading to anaemia.Methodology: Articles were searched in PubMed through screening of titles and abstracts with no limitation on date of publishing and study design. Articles in English were searched using keywords “African trypanosomiasis”, “sleeping sickness”, “Trypanosoma brucei”, in all possible combinations with “anaemia” and/or “cytokines”.Results: Twelve articles examining cytokines and their role in trypanosomeinduced anaemia were identified out of 1095 originally retrieved from PubMed. None of the articles identified were from human-based studies. A total of eight cytokines were implicated, with four cytokines (IFN-γ, IL-10, TNF-α, IL-12) showing an association with anaemia. These articles reported that mice lacking TNF-α were able to control anaemia, and that IFN-γ was linked to severe anaemia given its capacity to suppress erythropoiesis, while IL-10 was shown to regulate IFN-γ and TNF-α, providing a balance that was associated with severity of anaemia. IFN-γ and TNF-α have also been reported to work in concert with other factors such as nitric oxide and iron in order to induce anaemia.Conclusion: IFN-γ, IL-10, and TNF-α were the three major cytokines identified to beheavily involved in anaemia caused by Trypanosoma brucei infection. The anti-inflammatory cytokine, IL-10, was shown to counter the effects of proinflammatory cytokines in order to balance the severity of anaemia. The mechanism of anaemia is multifactorial and therefore requires further, more elaborate research. Data from human subjects would also shed more light

Does exposure to aflatoxin constrain efforts to reduce stunting in Zambia?

On 8 June 2013, the Vice President of Zambia stated that his government ‘is fully committed to reducing chronic undernutrition by 50 per cent in the next ten years…’ What are the challenges to meeting this goal? Zambia has both a high consumption of groundnuts and high levels of aflatoxin contamination of this commodity. Recent studies indicate an association between stunting and aflatoxin exposure. If the association exists, then Zambia faces serious challenges to reaching its target of 50 per cent reduction in chronic undernutrition. Recent efforts to identify atoxigenic strains for biocontrol in maize and groundnuts give cause for cautious optimism. Nonetheless, the challenges ahead demand both a high level of political will to achieve effective multisectoral collaboration and the willingness of the agricultural and health sectors to undertake rigorous monitoring of aflatoxin contamination and growth of young children, as well as the agricultural sector’s commitment to reduce substantially levels of aflatoxin contamination and to promote agricultural diversification

Operational research (ers) in development: Growing a new generation of operational researchers

This paper explores the theme of training operational research (OR) practitioners in South Africa by critically evaluating a Masters program in Operational Research in Development (ORD), launched in 2005 at the University of Cape Town. This program was specifically focused on applying OR to the problems of the developing world in general and Africa in particular. We describe the program and review the practical work undertaken by students participating in the program. Topics range widely across domains including health (anti-malarial drug resistance); poverty (food banking); governance (NGO management structures and monitoring of local government performance) and sustainable livelihoods (spaza shop operations). We use the review to highlight strengths and weaknesses of the program, as well as challenges faced in the OR education in South Africa at a postgraduate level

Non-communicable Lung Disease in Sub Saharan Africa: a Community-based Cross-sectional Study of Adults in Urban Malawi

Rationale Non-communicable diseases (NCD) are major causes of morbidity and mortality in sub-Saharan Africa (sSA). Valid burden of disease estimates are lacking for non-communicable lung disease in sSA. Objectives We performed a community-based survey to determine the prevalence of chronic lung disease amongst adults ≥18 years in Malawi, using ATS standard spirometry, internationally validated respiratory symptom and exposure questionnaires, and including assessment of HIV-status. Methods An age and gender stratified random sample of 2000 adults was taken from the population of Chilomoni district of Blantyre, Malawi. Fieldworkers collected questionnaire data, conducted HIV-testing and performed pre/post bronchodilator spirometry on eligible participants. Survey-weighted population prevalence estimates of respiratory symptoms and spirometric abnormalities were computed, and bivariate and multivariable regression were used to identify associated variables. Results Questionnaire data, HIV status and BOLD standard spirometry were obtained from 1059, 937 and 749 participants respectively. Current respiratory symptoms, exposure to biomass and ever smoking were reported by 11.8%, 85.2% and 10.4% respectively. HIV prevalence was 24.2%. Moderate-severe airway obstruction was seen in 3.6%. The prevalence of spirometric restriction was 38.6% using NHANES reference ranges and 9.0% using local reference ranges. Age was positively associated with obstruction while low BMI was associated with restriction. Conclusions Over 40% of the Malawian adults in our urban population-representative sample had abnormal lung function (mostly restrictive) in the context of widespread exposure to biomass smoke and high HIV prevalence. These findings have potentially major pubic health implications for Malawi and the broader sSA region

Effect of substituting animal protein sources with soybean meal in diets of Oreochromis karongae (Trewavas 1941)

Three diets were formulated using locally available feed ingredients in Malawi to test the effect of replacing animal protein (fish meal, meat and bone meal) with soybean meal (10:0, 5:5, 0:10% of diet) as the protein source on growth and feed conversion of Oreochromis karongae. There were no significant differences in growth rate (GR), specific growth rate (SGR) and feed conversion ratios (FCR) among the three diets. It can be concluded that more expensive and limited animal protein sources can totally be replaced by cheaper soybean in order to get similar growth rates in O. karongae

Apparent Insulin Deficiency in an Adult African Population With New-Onset Type 2 Diabetes

Identifying patients with new-onset type 2 diabetes who have insulin deficiency can aid in timely insulin replacement therapy. In this study, we measured fasting C-peptide concentration to assess endogenous insulin secretion and determine the prevalence and characteristics of patients with insulin deficiency in adult Ugandan patients with confirmed type 2 diabetes at presentation.MethodsAdult patients with new-onset diabetes were recruited from seven tertiary hospitals in Uganda. Participants who were positive for the three islet autoantibodies were excluded. Fasting C-peptide concentrations were measured in 494 adult patients, and insulin deficiency was defined as a fasting C-peptide concentration <0.76 ng/ml. The socio-demographic, clinical, and metabolic characteristics of participants with and without insulin deficiency were compared. Multivariate analysis was performed to identify independent predictors of insulin deficiency.ResultsThe median (IQR) age, glycated haemoglobin (HbA1c), and fasting C-peptide of the participants was 48 (39-58) years,10.4 (7.7-12.5) % or 90 (61-113) mmol/mol, and 1.4 (0.8-2.1) ng/ml, respectively. Insulin deficiency was present in 108 (21.9%) participants. Participants with confirmed insulin deficiency were more likely to be male (53.7% vs 40.4%, p=0.01), and had a lower body mass index or BMI [p<0.001], were less likely to be hypertensive [p=0.03], had reduced levels of triglycerides, uric acid, and leptin concentrations [p<0.001]), but higher HbA1c concentration (p=0.004). On multivariate analysis, BMI (AOR 0.89, 95% CI 0.85-0.94, p<0.001), non-HDLC (AOR 0.77, 95% CI 0.61-0.97, p=0.026), and HbA1c concentrations (AOR 1.08, 95% CI 1.00-1.17, p=0.049) were independent predictors of insulin deficiency.ConclusionInsulin deficiency was prevalent in this population, occurring in about 1 in every 5 patients. Participants with insulin deficiency were more likely to have high HbA1c and fewer markers of adiposity and metabolic syndrome. These features should increase suspicion of insulin deficiency and guide targeted testing and insulin replacement therapy

Impacts of Bacillus thuringiensis var. israelensis and Bacillus sphaericus insect larvicides on mosquito larval densities in Lusaka, Zambia

The study assessed the impact of bio-larvicides- Bacillus thuringiensis var. israelensis (Bti) and B. sphaericus (Bs) on anopheline mosquito larval densities in four selected areas of Lusaka urban district. Larval densities were determined using a standard WHO protocol at each study area prior to and after larviciding. Ninety percent (90%) of the collected mosquito larvae and pupae were preserved in 70% ethanol, while 10% were reared to adults for species identification. Prior to larviciding, the largest number of mosquito larvae collected was culicines. Among the anophelines, Anopheles coustani Laveran (13.5%) (n = 111) and An. squamosus Theobald (9.5%) (n = 78) were identified from all the study areas with An. rufipes Gough (1.1%) (n = 9) collected from one study area only. None of the major malaria vector species reported for Zambia were identified. No mosquito larvae were found in freshwater bodies following the larviciding exercise. Possible reasons for the absence of known major malaria vectors could be the re-introduction of effective vector control and loss of suitable breeding grounds. The study highlights the potential of larviciding using Bti and Bs for malaria vector control and its integration with indoor residual spraying and insecticide treated nets