12 research outputs found

    Calculation of Error between the Exact Solution and Solution of Parabolic Equation (Heat Equation) by Krylov Approximation Methods

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    Having good estimates in the computation of the approximation to expressions for the form f(A)v is very important in practical applications if we know at what stage the algorithm has to stop i.e avoid the principle of "luckybreak". In this paper we develop an a posteriori upper bound on the Krylov subspace approximation error. We seek the error committed between the exact solution and solution of parabolic equations(heat equation) by Krylov approximation methods.The idea of the method is to approximate the action of the evolution operator on a given state vector by means projection process onto a Krylov subspace. This estimate will allow us not only to theoretically study the behavior of the convergence of the Krylov method as well as its stability but also allow us to give the exact size of the Krylov space according to the fixed stop test and the precisions Wish to establish

    Revitalizing cultivation and strengthening the seed systems of fonio and Bambara groundnut in Mali through a community biodiversity management approach

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    Fonio (Digitaria exilis(Kippist)Stapf) and Bambara groundnut (Vigna subterranea(L.)Verdc.) are native crops grown at a small scale in Mali that have potential to support agricultural productivity under climate change. A community biodiversity management approach was explored in this study as a means to reinforce the cultivation of these crops by increasing farmers’ access to intraspecific diversity and developing capacities of community institutions for their management. The research involved six communities in Ségou and Sikasso regions. Multiple varieties of fonio (10–12) and Bambaragroundnut (8–12) were established indiversity fields in each site over 2 years where farmers engaged in experiential learning over the crop cycle. Significant adoption of fonio and Bambara groundnut was detected in several study sites.The precise drivers of adoption cannot be definitively determined but likely include increased seed access and awareness gained through the diversity field fora, seed fairs and community seed banks. No significant yield advantage was detected for any of the varieties in the diversity fields, which showed variable performance by site and year. The number of varieties registered and managed by community seed banks in each site increased from 1–5 varieties of each crop to 11–12 varieties following the interventions. The number of Bambara groundnut varieties cultivated in farmer as light decline in fonio diversity in some communities.The results of this study can inform efforts to strengthen seed systems and cultivation of neglected and underutilized species in Africa

    Prevalence and Intensity of Intestinal Parasites and Malaria in Pregnant Women at Abobo District in Abidjan, Côte d’Ivoire

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    A prospective study was carried out from 2010 to 2012 at the Hôpital Général d’Abobo (HGA) in Abidjan, in order to determine the impact of infectious and parasitic diseases on child cognitive development. Blood samples were examined by means of drop thick and blood smear, as for stool by direct examination and concentration by formalin-ether method. We evaluated the prevalence and the parasite load of malaria and gastrointestinal parasites and then investigated the risk factors for these disorders. Overall, 331 pregnant women in the last trimester of their pregnancy were enrolled. The plasmodic index was 3.9% with an infestation specific rate for P. falciparum of 100%. Concerning digestive protozoa, it has been observed 71.3% of nonpathogenic, against 9.7% of pathogens, either an overall prevalence of 51.4% of digestive parasites. The calculated average parasitic loads revealed 3089.2 tpz/μl of blood (95% CI, 591.1–5587.3) for malaria, 6.5 eggs per gram of stool (95% CI, 0.4–13.4) for intestinal helminths, and one (1) parasite by microscopic field for protozoa (common infestation). It has been shown that the occurrence of malaria has been linked to the nonuse of impregnated mosquito nets (χ2 = 0.012, p = 0.018) to age. No link could be established between the presence of digestive parasites and the age of pregnant women or socioeconomic conditions (level of education, profession, type of toilet). Malaria is less common in pregnant women, while the rate of digestive parasites remains high

    Epidemiology of intestinal parasite infections in three departments of south-central Côte d’Ivoire before the implementation of a cluster-randomised trial

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    Hundreds of millions of people are infected with helminths and intestinal protozoa, particularly children in low- and middle-income countries. Preventive chemotherapy is the main strategy to control helminthiases. However, rapid re-infection occurs in settings where there is a lack of clean water, sanitation and hygiene. In August and September 2014, we conducted a cross-sectional epidemiological survey in 56 communities of three departments of south-central Côte d’Ivoire. Study participants were invited to provide stool and urine samples. Stool samples were examined for helminth and intestinal protozoa infections using the Kato-Katz technique and a formalin-ether concentration method. Urine samples were subjected to a filtration method for the diagnosis of Schistosoma haematobium. Information on sociodemographic characteristics, knowledge, attitude, practices and beliefs with regard to hygiene, sanitation and intestinal parasitic diseases were collected using a questionnaire administered to household heads. Multivariable logistic regression models were employed to analyse associations between parasite infections and risk factors. Overall, 4,305 participants had complete parasitological and questionnaire data. Hookworm was the predominant helminth species (21.2%), while Ascaris lumbricoides, Trichuris trichiura, Schistosoma mansoni and S. haematobium showed prevalences below 10%. Infections with pathogenic intestinal protozoa (e.g. Entamoeba histolytica/E. dispar and Giardia intestinalis) were similarly prevalent in the three departments. Hookworm infection was associated with open defecation and participants' age and sex. Entamoeba coli infection was negatively associated with the use of tap water at home (odds ratio (OR) = 0.66; p = 0.032). Disposal of garbage in close proximity to people’s home was positively associated with G. intestinalis (OR = 1.30; p = 0.015). Taken together, helminth and intestinal protozoa infections affected a considerable proportion of rural dwellers in south-central Côte d’Ivoire at the onset of a cluster-randomised intervention trial. Our results will serve as baseline to monitor the effect of a package of interventions, including preventive chemotherapy, sanitation and health education on re-infection with helminths and intestinal protozoa

    Spatial assessment of nighttime anthropization in the Comoé National Park in Côte d’Ivoira (West Africa)

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    Protected areas play a crucial role in preserving biological diversity, providing ecosystem services, and regulating hydroclimatic processes. However, the environmental balance of these areas is increasingly under threat due to rapid population growth, high demand for natural resources, and the effects of global warming. To address this, sustainable management of protected areas is essential. This study aims to develop a methodology for monitoring and assessing levels of nocturnal anthropogenic aggression in the Comoé National Park (CNP) in Côte d’Ivoire. By using geospatial data from the Day/Night Band of the Visible Infrared Imaging Radiometer Suite (VIIRS/DNB), the study characterizes the nocturnal anthropization of CNP through the use of several indices. First, light reflectance density is used to identify nighttime light emission foci. Second, the lighted area density index (LADI) is employed to understand the nature of nocturnal activities taking place within CNP, as indicated by artificial light at night (ALAN). Finally, the light intensity index (LII) is used to evaluate the degree of influence of nocturnal anthropogenic activities on biodiversity. The study also found important activities through LADI and observed a high level of light pollution in CNP. Ultimately, the findings of this study indicate that there is a significant level of nocturnal anthropization within CNP, highlighting the need for effective management and conservation efforts in the area

    Clinical, Paraclinical, and Evolutionary Profiles of Kidney Failure in Gold Miners Hospitalized in a Nephrological Service in a Sub-Saharan African Country

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    Introduction. The purpose of this preliminary study is to describe the clinical, paraclinical, and evolutionary profiles of gold miner patients with kidney failure hospitalized in the nephrology and haemodialysis service in the Yalgado Ouédraogo University Hospital of Ouagadougou (CHU-YO). Patients and Methods. This was a longitudinal and descriptive study with a retrospective collection of data for the period from February 1, 2013, to March 31, 2018. Included were all gold miner patients who stayed and worked at an artisanal gold mining site for at least three months and who were diagnosed with acute or chronic kidney failure during hospitalization in the nephrology service. We collected sociodemographic, clinical, and paraclinical variables at admission and then three months later. Results. We included 50 patients; all were male and the average age was 29.4 ± 7.7 years. All patients were exposed to mercury and/or cyanide for an average of 4.5 ± 2.8 years. The average consultation/referral time for patients at the CHU-YO was 25.4 ± 14.9 days. The average of creatininemia was 2338.0 ± 791.4 μmol/L. Kidney failure was acute in five cases (10%) and chronic in the remaining 45 cases or 90%. Extrarenal purification was indicated in 43 cases (86%). It was not performed in nine of the 43 cases due to lack of financial resources for patients (six cases) or death prior to the onset of haemodialysis (three cases). Thirty-two of the 50 patients in the study (64% of cases) died. Conclusion. Chronic kidney failure in gold miners appears to be common and late-managed. A prospective study of kidney disease and its causes at gold mining sites and surrounding areas will assess the extent of the problem in the country and better clarify the prevention of these diseases in our country

    Urban expansion of Korhogo City (Côte d’Ivoire) using gis and nocturnal remote sensing

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    Abstract Temporal data series of stable Artificial Lights At Night (ALAN) obtained from sources such as DMSP/OLS and VIIRS/DNB provide valuable insights into the dynamics of urban expansion. This study introduces a novel methodology for characterizing urban boundaries, which combines textural analysis utilizing the Co-occurrence matrix and urban surface delineation employing the Wombling contour detection algorithm. Applying this method to the city of Korhogo in northern CĂ´te d'Ivoire, the findings reveal an irregular and gradual evolution of urban surfaces between 1992 and 2012, with a rate of change of 35 km2. However, starting from 2012, a rapid urbanization process is observed, continuing until 2020, characterized by an evolution rate of approximately 45 km2. Considering the significant urban expansion witnessed in the city of Korhogo, it is imperative to implement appropriate urban management strategies and measures for ecosystem protection

    Effectiveness of Three Sampling Approaches for Optimizing Mapping and Preventive Chemotherapy against <i>Schistosoma mansoni</i> in the Western Part of Côte d’Ivoire

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    The elimination of schistosomiasis as a public health problem by 2030 is one of the main goals put forth in the World Health Organization’s roadmap for neglected tropical diseases. This study aimed to compare different sampling approaches to guide mapping and preventive chemotherapy. A cross-sectional parasitological survey was conducted from August to September 2022 in the health districts of Biankouma, Ouaninou, and Touba in the western part of Côte d’Ivoire. The prevalence and intensity of Schistosoma mansoni infection were assessed in children aged 5–14 years using three sampling approaches. The first approach involved a random selection of 50% of the villages in the health districts. The second approach involved a random selection of half of the villages selected in approach 1, thus constituting 25% of the villages in the health district. The third approach consisted of randomly selecting 15 villages from villages selected by approach 2 in each health district. The overall prevalence of S. mansoni was 23.5% (95% confidence interval (CI): 19.9–27.6%), 21.6% (95% CI: 17.1–26.8%), and 18.3% (95% CI: 11.9–27.1%) with the first, second, and third approach, respectively. The respective geometric mean S. mansoni infection intensity was 117.9 eggs per gram of stool (EPG) (95% CI: 109.3–127.3 EPG), 104.6 EPG (95% CI: 93.8–116.6 EPG), and 94.6 EPG (95% CI 79.5–112.7 EPG). We conclude that, although randomly sampling up to 50% of villages in a health district provides more precise population-based prevalence and intensity measures of S. mansoni, randomly selecting only 15 villages in a district characterized by low heterogeneity provides reasonable estimates and is less costly

    Clinical risk factors associated with multidrug-resistant tuberculosis (MDR-TB) in Mali

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    Background: MDR-TB is a major threat to global TB control. In 2015, 580,000 were treated for MDR-TB worldwide. The worldwide roll-out of GeneXpert MTB/RIF® has improved diagnosis of MDR-TB; however, in many countries laboratories are unable to assess drug resistance and clinical predictors of MDR-TB could help target suspected patients. In this study, we aimed to determine the clinical factors associated with MDR-TB in Bamako, Mali. Methods: We performed a cross-sectional study of 214 patients with presumed MDR-TB admitted to University of Bamako Teaching Hospital, Point-G between 2007 and 2016. We calculated crude and adjusted odds ratios for MDR-TB disease diagnosis using SPSS. Results: We found that age ≤40 years (OR = 2.56. 95% CI: 1.44–4.55), two courses of prior TB treatment (OR = 3.25, 95% CI: 1.44–7.30), TB treatment failure (OR = 3.82, 95% CI 1.82–7.79), sputum microscopy with 3+ bacilli load (OR = 1.98, 95% CI: 1.13–3.48) and a history of contact with a TB patient (OR = 2.48, 95% CI: 1.11–5.50) were significantly associated with confirmation of MDR-TB disease. HIV was not a risk factor for MDR-TB (aOR = 0.88, 95% CI: 0.34–1.94). Conclusion: We identified several risk factors that could be used to identify MDR-TB suspects and prioritize them for laboratory confirmation. Prospective studies are needed to understand factors associated with TB incidence and clinical outcomes of TB treatment and disease. Keywords: Multi-Drug Resistant Tuberculosis, Risk factors, Mal
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