1,304 research outputs found

    Time domain simulations of dynamic river networks

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    The problem of simulating a river network is considered. A river network is considered to comprise of rivers, dams/lakes as well as weirs. We suggest a numerical approach with specific features that enable the correct representation of these assets. For each river the flow of water is described by the shallow water equations which is a system of hyperbolic partial differential equations and at the junctions of the rivers, suitable coupling conditions, viewed as interior boundary conditions are used to couple the dynamics. A different model for the dams is also presented. Numerical test cases are presented which show that the model is able to reproduce the expected dynamics of the system. Other aspects of the modelling such as rainfall, run-off, overflow/flooding, evaporation, absorption/seepage, bed-slopes, bed friction have not been incorporated in the model due to their specific nature

    High dose multiple micronutrient supplementation improves villous morphology in environmental enteropathy without HIV enteropathy: results from a double-blind randomised placebo controlled trial in Zambian adults

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    PMCID: PMC3897937This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated

    Local production of pharmaceuticals and health system strengthening in Africa

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    Low-income populations in sub-Saharan Africa (SSA) continue to suffer inadequate health care, undermined by poor access to medicines. In the context of Sustainable Development Goal (SDG) 3 and international commitments to universal health coverage (UHC), international intervention finances large-scale international procurement of medicines and supports health system strengthening. Meanwhile, pharmaceutical manufacturing in SSA is long established, and is currently being promoted by African governments and other actors including the African Union Commission (AUC), the New Partnership for Africa’s Development (NEPAD) and the East African Community (EAC), and supported also by external actors including Germany’s Federal Ministry for Economic Cooperation and Development (BMZ). This Brief presents evidence for the actual and potential health and development benefits from creating stronger local and global linkages between these industrial and health agendas, and outlines how this can be done

    Higgs boson hadronic branching ratios at the ILC

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    We present a study of the Higgs boson decay branching ratios to bbˉb\bar{b}, ccˉc\bar{c} and gluons, one of the cornerstones of the physics program at the International Linear Collider (ILC). A standard model Higgs boson of 120\,GeV mass, produced in the Higgs-strahlung process at s=250\sqrt{s} = 250\,GeV was investigated using the full detector simulation and reconstruction procedures. The analysis was performed in the framework of the Silicon Detector (SiD) concept with full account of inclusive standard model backgrounds. The selected decay modes contained two heavy flavour jets in the final state and required excellent flavour tagging through precise reconstruction of interaction and decay vertices in the detector. A new signal discrimination technique using correlations of neural network outputs was used to determine the branching ratios and estimate their uncertainties, 4.8\%, 8.4\% and 12.2\% for bbˉb\bar{b}, ccˉc\bar{c} and gluons respectively.Comment: 9 Pages, 5 figures and 5 table

    Correlation between sunshine hours and climatic parameters at four locations in Uganda

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    One of the most important factors in solar energy production is related to the predictability of sunshine hours. The objective of this study is to assess the correlation between sunshine hours and relative humidity, cloud cover, maximum and minimum temperature, for the purpose of identifying the most appropriate parameter(s) for the prediction of sunshine hours in Uganda. Climatic data for the meteorological stations of Entebbe, Mbarara, Tororo and Makerere, extending over a period of 15 years (1990-2005) was collected from the Department of Meteorology, Kampala. The data set included maximum temperature, minimum temperature, relative humidity at 6 am and at 12 noon, Cloud cover at 6 am and at 12 noon and Sunshine hours. A multiple regression technique was used to assess the correlation between sunshine hours and maximum and minimum temperatures, cloud cover at 6 am and at 12 noon and relative humidity at 6 am and at 12 noon. Results have shown that the availability of sunshine hours can be predicted by the use of maximum and minimum temperatures, relative humidity at 6 am and 12 noon and cloud cover at 6 am and at 12 noon in Uganda, but, principal components and factoraAnalysis have indicated that two parameters, especially relative humidity at noon or 6 am and Maximum temperature are enough to capture the variability of sunshine hours in Uganda

    Shift-Symmetric Configurations in Two-Dimensional Cellular Automata: Irreversibility, Insolvability, and Enumeration

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    The search for symmetry as an unusual yet profoundly appealing phenomenon, and the origin of regular, repeating configuration patterns have long been a central focus of complexity science and physics. To better grasp and understand symmetry of configurations in decentralized toroidal architectures, we employ group-theoretic methods, which allow us to identify and enumerate these inputs, and argue about irreversible system behaviors with undesired effects on many computational problems. The concept of so-called configuration shift-symmetry is applied to two-dimensional cellular automata as an ideal model of computation. Regardless of the transition function, the results show the universal insolvability of crucial distributed tasks, such as leader election, pattern recognition, hashing, and encryption. By using compact enumeration formulas and bounding the number of shift-symmetric configurations for a given lattice size, we efficiently calculate the probability of a configuration being shift-symmetric for a uniform or density-uniform distribution. Further, we devise an algorithm detecting the presence of shift-symmetry in a configuration. Given the resource constraints, the enumeration and probability formulas can directly help to lower the minimal expected error and provide recommendations for system's size and initialization. Besides cellular automata, the shift-symmetry analysis can be used to study the non-linear behavior in various synchronous rule-based systems that include inference engines, Boolean networks, neural networks, and systolic arrays.Comment: 22 pages, 9 figures, 2 appendice

    Soy dairy performance metrics

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    Soybean (Glycine max (L. Merr.) has been a crop of interest to address both poverty and malnutrition in the developing world because of its high levels of both protein and oil, and its adaptability to grow in tropical environments. Development practitioners and policymakers have long sought value added opportunities for local crops to move communities out of poverty by introducing processing or manufacturing technologies. Soy dairy production technologies sit within this development conceptual model. To the researchers’ knowledge, no research to date measures soy dairy performance, though donors and NGOs have launched hundreds of enterprises over the last 18 years. The lack of firm-level data on operations limits the ability of donors and practitioners to fund and site sustainable dairy businesses. Therefore, the research team developed and implemented a recordkeeping system and training program first, as a 14-month beta test with a network of five dairies in Ghana and Mozambique in 2016-2017. Learning from the initial research then supported a formal research rollout over 18 months with a network of six different dairies in Malawi and key collaboration from USAID’s Agricultural Diversification activity. None of the beta or rollout dairies kept records prior to the intervention. The formal rollout resulted in a unique primary dataset to address the soy dairy performance knowledge gap. The results of analysis show that the dairies, on average, achieve positive operating margins of 61%, yet cannot cover the fixed costs associated with depreciation, amortization of equipment and infrastructure, working capital, marketing and promotion, and regulatory compliance. The enterprises in our sample operate only at 9% of capacity, which limits their ability to cover the normal fixed costs associated with the business. The challenge is not thetechnology itself, as when operated, it produces a high-quality dairy product. The challenges involve a business that requires too much capital for normal operations relative to a nascent and small addressable market

    Language policy and orthographic harmonization across linguistic, ethnic and national boundaries in Southern Africa

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    Drawing on online and daily newspapers, speakers' language and writing practices, official government documents and prescribed spelling systems in Southern Africa, the paper explores the challenges and possibilities of orthographic reforms allowing for mobility across language clusters, ethnicity, regional and national borders. I argue that this entails a different theorisation of language, and for orthographies that account for the translocations and diasporic nature of late modern African identities and lifestyles. I suggest an ideological shift from prescriptivism to practice-orientated approaches to harmonisation in which orthographies are based on descriptions of observable writing practices in the mobile linguistic universe. The argument for orthographic reforms is counterbalanced with an expose on current language policies which appear designed for an increasing rare monoglot 'standard' speaker, who speaks only a 'tribal' language. The implications of the philosophical challenges this poses for linguists, language planners and policy makers are thereafter discussed.IS

    Prevalence and Factors Associated with Renal Dysfunction in HIV Positive and Negative Adults at the University Teaching Hospital, in Lusaka

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    Background: Despite having the highest disease burden of HIV, Sub-Saharan Africa has limited data on HIV related kidney disease with most available data coming from the developed countries. Kidney disease is a recognised complication in HIV infected patients presenting with acute renal failure (ARF) or chronic kidney disease (CKD). This study investigated the prevalence and risk factors associated with renal dysfunction among hospitalised HIV infected patients at the University Teaching Hospital (UTH), Lusaka.Methodology:We conducted a cross sectional study at the University Teaching Hospital Lusaka, in Zambia. Inclusion criteria were hospitalised patients aged 16years and above who consented to the study. Both HIV infected and uninfected patients were included in the study. After obtaining demographic information, study participants were screened for HIV upon their consenting for the test. Afull clinical history and examination was done by study physician to determine factors associated with renal dysfunction.Results: Of the 300 recruited hospitalised patients in this cross sectional study, 142(47%) were HIV infected. We observed a high prevalence of renal dysfunction among hospitalised HIV infected patients compared to uninfected patients (42% vs. 27%, adjusted OR 1.99, 95% CI 1.20-3.28). They had a twofold increased likelihood of developing kidney dysfunction (OR 1.96,95 CI%; 1.21-3.17). The presence of vomiting was strongly associated with renal dysfunction in both HIV positive (AOR 7.77, 95% CI 2.46-24-53) and negative (AOR4.83, 95%CI 1.40-16.66) subgroups. WHO stage III was associated with renal dysfunction in HIV infected patients. Tenofovir use, (a first line antiretroviral drug in Zambia) and hypotension were not significant factors associated with kidney disease after adjusting for other clinical parameters.Conclusion: Renal dysfunction is significantly higher among hospitalised HIV infected compared to uninfected, however tenofovir and hypotension were not associated with renal dysfunction.Keywords: Renal dysfunction, HIV, acute renal failure, vomitin

    Implementing Groundness Analysis with Definite Boolean Functions

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    The domain of definite Boolean functions, Def, can be used to express the groundness of, and trace grounding dependencies between, program variables in (constraint) logic programs. In this paper, previously unexploited computational properties of Def are utilised to develop an efficient and succinct groundness analyser that can be coded in Prolog. In particular, entailment checking is used to prevent unnecessary least upper bound calculations. It is also demonstrated that join can be defined in terms of other operations, thereby eliminating code and removing the need for preprocessing formulae to a normal form. This saves space and time. Furthermore, the join can be adapted to straightforwardly implement the downward closure operator that arises in set sharing analyses. Experimental results indicate that the new Def implementation gives favourable results in comparison with BDD-based groundness analyses
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