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Sq (H) Solar Variation at Yaoundé-Cameroon AMBER Station from 2011 to 2014

International Journal of Geosciences 2017年第4期8卷 545-562页

作者： messanga etoundi honoré Fatma Anad Ngabireng Claude Marie Mbane Biouele César Laboratory of Earth’s Atmosphere Physics Department of Physics University of Yaoundé 1 Yaoundé Cameroon Centre de Recherche en Astronomie Astrophysique et géophysique Algiers Algéria Laboratory of non-linear Physics-ENSP University of Yaoundé 1 Yaoundé Cameroon

This paper presents the earth’s magnetic field variations on quiet days using data from 2011 to 2014 provided by the AMBER station located at the University of Yaoundé 1 (Cameroon), whose geographic and geomagnetic coordinates are respectively: (3.87°N, 11.52°E) and (5.8°S, 83.1°E). The variability of the H horizontal component of the Earth’s magnetic field was examined using the North (X) and East (Y) components of the earth’s magnetic field. The H component is then used to calculate and analyze the diurnal, monthly and seasonal Solar quiet variations Sq (H) observed in Yaoundé-Cameroon during quiet magnetic days. The results obtained show that the Sq (H) variations are seasonal. e.g., in Spring the Sq (H) amplitude (~72 nT) is larger than that of Autumn (~69 nT). The maximum values of Sq (H) vary from 48.8 nT to 57.12 nT in summer and from 41 nT to 60 nT in winter from the years 2011 to 2014. In general, these maximum values are observed around 12:00 and 13:00 in local time. These results show that the morphology of Sq (H) in Yaoundé is presented as a function of seasons. Moreover, the Sq (H) values are negative during morning hours (01:00 - 06:00) and afternoon hours (18:00 - 24:00) in local time throughout all months and all seasons. This significant negative excursion of Sq (H) in Yaoundé during the night time might be due to other physical processes such as storms or thunderclouds or to the existence of a strong induced current in Yaoundé which can affect the ground-based instruments. By referring to the solar cycle 24, our results show that the Sq (H) amplitude varies with the solar activity. The aim of this work is to analyze the diurnal, monthly and seasonal variations of Sq (H) observed in Yaoundé from 2011 to 2014.

关键词： Sq (H) Amplitude Sq (H) Diurnal Monthly and Seasonal Variations Solar Cycle 24

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Longitudinal Variability of the Vertical Drift Velocity Inferred from Ground-Based Magnetometers and C/NOFS Observations in Africa

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International Journal of Geosciences 2022年第8期13卷 657-680页

作者： messanga etoundi honoré Paul Obiakara Amaechi Augustin Daïka Diaby Kassamba Abdel Aziz Mohamed Kaab César Biouele Mbané Zouhair Benkhaldoun Department of Geomatics Higher Technical Teacher Training College of Ebolowa University of Ebolowa Ebolowa Cameroon Applied Biotechnology and Engineering Laboratory Higher Technical Teacher Training College of Ebolowa Ebolowa Cameroon Laboratory of Earth’s Atmosphere Physics Faculty of Science University of Yaoundé 1 Yaoundé Cameroon Cardiff School of Education & Social Policy Cardiff Metropolitan University Cyncoed Campus Cardiff UK Department of Meteorology and Climatology National Advanced School of Engineering University of Maroua Maroua Cameroon Laboratoire de Physique de l’Atmosphère UFR-SSMT Université Félix Houphou&#235 t Boigny Abidjan C&#244 te d’Ivoire Oukaimeden Observatory LPHEA FSSM Cadi Ayyad University Marrakech Morrocco National School of Applied Sciences of Beni Mellal Sultan Moulay Sliman University Beni Mellal Morocco

This study aims at discussing longitudinal effects on the variability of the vertical E × B drift velocity at low latitudes, specifically over African sector. To this effect, observations from ground-based magnetometers and the Ion Velocity Meter experiment onboard C/NOFS satellite are analyzed in conjunction with equatorial electric field and neutral wind model estimates under geomagnetically quiet conditions in the years 2012-2013. Notwithstanding the limitation in data over Africa, the combination of ground-based and in-situ observations confirmed the existence of longitudinal differences in the E × B between the Atlantic, Western and Eastern African sectors. This was well reproduced by the equatorial electric field model (EEFM) which showed that during noon, the peak of the equatorial electric field (EEF) was the lowest in the Atlantic sector, with an increasing trend towards the Eastern longitude. The Horizontal Wind Model 14 (HWM14) showed that the eastward zonal (poleward meridional) wind velocity was the lowest (highest) in the Eastern sector. Furthermore, the zonal (meridional) wind increased (decreased) from the Eastern to the Atlantic sector. These results highlight the contribution of the neutral wind velocity in driving the longitudinal difference in the vertical drift velocity over Africa.

关键词： Equatorial Electrojet Vertical Drift Velocity (E × B) Longitudinal Variability African Sector

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Longitudinal Variability of the Vertical Drift Velocity Inferred from Ground-Based Magnetometers and C/NOFS Observations in Africa

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International Journal of Geosciences（地球科学国际期刊） 2022年第8期

作者： messanga etoundi honoré paul obiakara amaechi augustin daïka diaby kassamba abdel aziz mohamed kaab césarbiouelembané zouhair benkhaldoun

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Gold Mineralisation in the Intiédougou Prospect (Diébougou District) in Southwest Burkina Faso, West African Craton

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Journal of Minerals and Materials Characterization and Engineering 2024年第1期12卷 63-77页

作者： Yao honoré Koffi Wendkouni Passecdé Pauline Zongo Nanema Mathieu Urbain Wenmenga Département de Géosciences UFR Sciences Biologiques Université Peleforo Gon COULIBALY Korhogo C&#244te d’Ivoire UFR Sciences et Technologie Université de Ouahigouya Ouahigouya Burkina Faso Département des Sciences de la Terre UFR Sciences de la Vie et de la Terre Université Ouaga I Pr. Joseph KI-ZERBO Ouagadougou Burkina-Faso

The Intiédougou located in the Houndé Birimian greenstone belt has been the subject of several mining and geoscience studies that have led to the discovery of mineralized gold targets. One of these mineralized targets has prompted work that raises the issue of control factors for the gold mineralization of the prospect. The methodology used in this study combines a study of core drill hole data located in the area and laboratory studies. The Intiédougou sector is based on andesito-basaltic, andesitic interstratified volcanoclastite rocks and Tarkwaïen type detrital sedimentary rocks caught in a vice in the volcano-sedimentary unit. Lithostructural analysis of the sector shows that the subvolcanic rocks bearing gold mineralization are subjected to heterogeneous ductile to brittle deformations and affected by hydrothermalism evolving at stages marked by large fissure fillings. These hydrothermal phases evolve in the zones of expansion created by the brittle deformations that have contributed to the deposits of different types of gold-enriched sulphides. These different phases of hydrothermal destabilization generally of low degree accompany the tardi to post-eburnean brittle tectonics. This deformation system is favorable to the establishment of gold mineralization in the form of vein bodies. The overimposition of deformed and altered areas suggests a genetic relationship between deformation and hydrothermal activity. In conclusion, the mineralization of Intiédougou in vein styles, set up in a volcanic arc environment with a paragenesis of gold-pyrite deposit ± chalcopyrite would be controlled by the structural aspect and accompanied by hydrothermal alteration.

关键词： Intiédougou Prospect Shear Hydrothermal Tarkwaïan Gold Mineralization

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Effect of Size and Initial Water Content on the Effective Diffusion Coefficient during Convective Drying of Sweet Potato Cut into Cubic and Cylindrical Shapes

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Journal of Materials Science and Chemical Engineering 2024年第6期12卷 71-82页

作者： Ibrango Abdoul Salam Ouoba Kondia honoré Bama Désiré Traoré Yssa Zongo Karim Ouedraogo Salifou Laboratoire de Matriaux de lHliophysique et Environnement (La.M.H.E.) Unit de Formation et de Recherche en Sciences. Exactes et Appliques (UFR/SEA) Universit Nazi BONI de Bobo-Dioulasso Bobo-Dioulasso Burkina Faso

In this article, we investigated the influence of size and initial water content on the effective diffusion coefficient of sweet potatoes samples cut into cubic and cylindrical shapes. The sizes of the cubic samples are 0.5, 1, 1.5, 1.75, 2, 2.5 and 3 cm edge with a respective initial water content of 2.7, 3.76, 3.48, 2.68, 3.28, 2.17 and 2.29 kg/kgms. For cylindrical samples, the radius is set at 0.5 cm and sample heights are 1, 1.5, 2, 2.5, 3, 3.5 and 4 cm with respective water contents of 2.2, 3.19, 2.85, 2.1, 2.17, 2.39 and 2.03 kg/kgms. The effective diffusion coefficients of cubic samples are of the order of 10−10 and 10−9 m2∙s−1 grew with sample edge. As for the cylindrical samples, the effective diffusion coefficients were of the order of 10−9 m2∙s−1 and there was no linear correlation between cylinder height and their effective diffusion coefficient. As for the examination of the initial water content on the effective diffusion coefficient, it turned out that the initial water content had no influence on the effective diffusion coefficient of the sweet potato samples.

关键词： Effective Diffusion Coefficient Initial Water Content Sweet Potato Cubic Cylindrical

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Mitigating Iron Toxicity by Using Rock Phosphate to Improve Rice Productivity

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Agricultural Sciences 2024年第4期15卷 423-438页

作者： Adama Bagayogo honoré Kam Jacques Sawadogo Moumouni Konate Moussa Sie Satoshi Nakamura Fujio Nagumo Mahamadou Sawadogo Ouaga I Uviversity Jospeph Ki-Zerbo Life and Earth Sciences Training and Research Unit (UFR/SVT) Ouagadougou Burkina Faso National Center for Scientific and Technological Research National Institute of Environment and Agricultural Research (INERA) Bobo-Dioulasso Burkina Faso Japan International Research Center for Agricultural Sciences Ibaraki Japan

Iron toxicity is a major constraint to rice production, particularly in highly weathered soils of inland valleys in Sub-Saharan Africa where the rice growing area is rapidly expanding. This study aimed to improve the productiveness of iron toxicity sensitive’s rice fields as well as in the unsensitive fields by using local phosphate fertilizers. Eighteen (18) rice genotypes were been assessed in a split plot design in two areas: without iron toxicity and with iron toxicity. NPK, NK, Rock Phosphate, Triple super phosphate, Calcined phosphate and Acidulated phosphate were used as fertilizers. Data collection was focused on agronomic traits and yield (g/m2). The best fertilizers in the area without iron toxicity were NPK (820.2 g/m2) and triple super phosphate (751.7 g/m2). In the iron toxicity area, the best yields were performed by NPK (785.5 g/m2) and raw calcined phosphate (698.3 g/m2). Yet, the Accessions 15, Accessions 225, Accessions 226 and Accessions 270 were rainfed rice genotypes while CC109 A, HB 46 and HB 62 were low-land/irrigated rice genotypes. NPK, NK and acidulated phosphate fertilizers alleviate the best, iron toxicity in both sensitive and unsensitive rice fields.

关键词： Oryza NPK NK Rock Phosphate Rice

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Production of Yam Tubers Using Seed Tubers from Vitroplants Regenerated from Aerial Stems in the Yam Species Dioscorea alata (L.) and Dioscorea cayenensis-rotundata (L. & P.) in Côte d’Ivoire

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Advances in Bioscience and Biotechnology 2024年第3期15卷 184-194页

作者： Koffi honoré Kouamé Kouakou Marius Konan Kouadio Ignace Kouassi Kouablan Edmond Koffi Assanvo Simon-Pierre N’Guetta Department of des Science and Technology University Alassane Ouattara of Bouaké Bouaké C&#244te d’Ivoire Plant Production Research Unit Department of Natural Sciences University Nangui Abrogoua Abidjan C&#244te d’Ivoire Central Biotechnology Laboratory National Center for Agronomic Research (NCAR) Abidjan C&#244te d’Ivoire Genetics Laboratory of Bioscience Research Unit University Félix Houphou&#235t Boigny (UFHB) Abidjan C&#244te d’Ivoire

The aim of this study is to produce large quantities of yam tubers in the field from seed tubers derived from vitroplants regenerated from aerial stem cuttings and farmers’ tuber seeds. Seed tubers from ten yam cultivars, including five from Dioscorea alata (cDa083, cDa053, cDa115, cDa150 and cDa266) and five from Dioscorea cayenensis-rotundata (cDr015, cDr027, cDr150, cDr206 and cDr148) with distinct agro-morphological characteristics, were used as material. A completely randomized block design with 3 replications was used. In each block, all cultivars and seed types were represented. When put into cultivation, the tubers produced by the vitroplants all germinated and gave 100% healthy plants, compared with 86% to 100% healthy plants for the seed tubers produced by the farmers. Yields per hectare ranged from 10 to 25 tonnes for seed tubers produced by in vitro plants, and from 4 to 9 tons for seed tubers produced by farmers. Seed tubers from vitroplants can therefore be recommended to farmers as a solution to the problem of seed tuber unavailability.

关键词： Yams Vitroplants Seed Tubers Yields

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Physical Transformations on Organic Product during Its Convective Drying: Case of Sweet Potato

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Journal of Biophysical Chemistry 2024年第2期15卷 25-34页

作者： Ouoba Kondia honoré Ganamé Abdou-Salam Compaoré Aboubakar Ibrango Abdoul Salam Bama Désiré Zougmoré Francois Desmorieux Hélène Laboratoire de Matriaux de lHliophysique et Environnement (La.M.H.E.) Unit de Formation et de Recherche en Sciences Exactes et Appliques (UFR/SEA) Universit Nazi BONI Bobo Dioulasso Burkina Faso Laboratoire des Matriaux et Environnement (LA.M.E.) Unit de Formation et de Recherche en Sciences Exactes et Applique (UFR/SEA) Universit Joseph KI-ZERBO Ouagadougou Burkina Faso Laboratoire de Physique et de Chimie de lEnvironnement (LPCE) Ecole Doctorale Sciences et Technologie (ED-ST) Universit Joseph KI-ZERBO Ouagadougou Burkina Faso Laboratoire dAutomatique et de Gnie des Procds(LAGEP) Universit Claude Bernard Lyon France

This study highlighted the physical transformation that agri-food products undergo during their drying. This transformation enormously affects the customer’s choice and the profit margin of the dried product promoter. The example of the experimental study of the potato reveals that the product continually changes its dimensions during its drying. The more the product loses its water, the more the dimensions decrease. The results initially showed that the water parameters such as mass or water content decrease according to the drying principle. The dimensions length L., width l and thickness e. decrease following a linear trend whose mathematical equations which describe them are determined using the office tool, excel. This trend has repercussions on the surface and volume parameters which in turn decreases almost linearly with the product’s water content. Note that the coefficient R2 is not always acceptable, confirming the complex nature of the behavior of organic products.

关键词： Dimensions Reduction Shrinkage Index I

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Estimation of the Direct Cost of Management of Venous Thromboembolism in Three Reference Hospitals in the City of Yaoundé: A Retrospective Study over a Three-Year Period

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World Journal of Cardiovascular Diseases 2024年第2期14卷 99-114页

作者： Hamadou Ba Nganou-Ngnindjio Chris Nadège Tatchim Samuel Aimé Kamdem Félicité Tchoukoua Serge honoré Ahmadou Jingi Danwe Dieudonne Kingue Samuel Faculty of Medicine and Biomedical Sciences University of Yaoundé I Yaoundé Cameroon Department of Internal Medicine Garoua General Hospital Garoua Cameroon Cardiology Department Yaoundé Central Hospital Yaoundé Cameroon Higher Institute of Health Sciences University of the Mountains Bagangté Cameroon Faculty of Medicine and Pharmaceutical Sciences University of Douala Douala Cameroon Department of Internal Medicine Douala General Hospital Douala Cameroon Faculty of Health Sciences University of Bamenda Bamenda Cameroon Cardiology Department Yaoundé General Hospital Yaoundé Cameroon

Background: Venous thromboembolism (VTE) is a major public health problem due to its increasing frequency, mortality and management cost. This cost may require major financial efforts from patients, especially in developing countries like ours where less than 7% of the population has health insurance. This study aimed to estimate the direct cost of managing VTE in three reference hospitals in Yaoundé. Methods: This was a cross-sectional retrospective study over a three-year period (from January 1st 2018 to December 31 2020) carried out in the Cardiology departments of the Central and General Hospitals, and the Emergency Centre of the city of Yaoundé. All patients managed during the study period for deep vein thrombosis and pulmonary embolism confirmed by venous ultrasound coupled with Doppler and computed tomography pulmonary angiography respectively were included. For each patient, we collected sociodemographic and clinical data as well as data on the cost of consultation, hospital stay, workups and medications. These data were analysed using SPSS version 23.0. Results: A total of 92 patient’s records were analysed. The median age was 60 years [48 - 68] with a sex ratio of 0.53. The median direct cost of management of venous thromboembolism was 766,375 CFAF [536,455 - 1,029,745] or $1415 USD. Management of pulmonary embolism associated with deep vein thrombosis was more costly than isolated pulmonary embolism or deep vein thrombosis. Factors influencing the direct cost of management of venous thromboembolism were: hospital structure (p = 0.015), health insurance (p 0.001), type of pulmonary embolism (p = 0.021), and length of hospital stay (p = 0.001). Conclusion: Management of VTE is a major financial burden for our patients and this burden is influenced by the hospital structure, health insurance, type of pulmonary embolism and length of hospital stay.

关键词： Cost Management Venous Thromboembolism Yaoundé

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Nephroblastoma in Adults about a Clinical Case

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Surgical Science 2024年第2期15卷 81-88页

作者： Tounkara Cheickna Coulibaly Amara Malle Oumar Amadou Bréhima Bolo Coulibaly Bagoyoko Kaloga Daye Samake Hamidou Berthe honoré Jean-Baptiste Gabriel Diakite Mamadou Lamine Department of General Surgery Hospital Center “Mother Child” Luxembourg Bamako Mali Directorate of Army Health Services Kati Mali Department of Urology and Andrology Point G University Hospital Bamako Mali

Nephroblastoma is the most common malignant renal tumor in children and is related to an abnormal proliferation of cells resembling those of the embryonic kidney (metanephroma), hence the terminology;embryonal tumor. These are tumors that remain and remain unstudied in Mali because they are common in adults in our context. Its annual incidence is estimated at approximately 1/10,000 births. Nephroblastoma is a rare or even exceptional tumor in adults. The clinical manifestation was a large swelling of the right hypochondrium;abdominal pain for a year;unquantified fever, hypertension, initial hematuria associated with burning during urination and anemia. The main clinical manifestation remained fever and abdominal pain. This renal tumor posed a diagnostic problem which was previously labeled as a mesenteric tumor in our general surgery department. The diagnosis was made by imaging: CT and magnetic resonance imaging. The treatment is multidisciplinary and combines chemotherapy, surgery with or without radiotherapy. The prognosis is poor due to late diagnosis and less effectiveness of chemotherapy compared to the child. Survival did not exceed a year and a half because the renal tumor in our patient was surgically overcome. We report a case of nephroblastoma in an 86-year-old patient with unfavorable histology (hematogenous metastases), operated on in the general surgery department and whose postoperative course was simple and who was referred to oncology for treatment.

关键词： Nephroblastoma Malignant Kidney Tumor Treatment Adult Mali

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