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Land use impact on clay dispersion/flocculation in irrigated and flooded vertisols from Northern Cameroon

International Soil and Water Conservation Research 2018年第3期6卷 237-244页

作者： Simon djakba Basga désirétsozue Jean Pierre Temga Jules Balna Jean Pierre Nguetnkam Institute of Agricultural Research for development(IRAd) P.O.Box33MarouaCameroon department of Earth Sciences Faculty of ScienceUniversity of MarouaP.O Box814MarouaCameroon department of Earth Sciences Faculty of ScienceUniversity of Yaoundé1P.O Box812YaoundéCameroon department of Earth Sciences Faculty of ScienceUniversity of NgaoundéréP.O Box454NgaoundéréCameroon

Clay dispersion by water is important for soil and water conservation as well as for irrigation scheduling. In the present study, clay dispersion/flocculation of irrigated and flooded vertisols in North Cameroon was investigated using clay dispersion/stability indices. Nine vertisols topsoils (0–20 cm) samples were collected on different land use and their clay dispersion indices were assessed. Vertisols were acidic to slightly basic, with smectites as dominant clay mineral. The water dispersible clay (160–340 g kg-1), the dispersion ratio (0.55–0.79) and the clay dispersion ratio (0.48–0.83) were high in the studied vertisols while the clay flocculation index (0.17–0.54) and the clay aggregation (70–230 g kg-1) were low to moderate, indicating their high dispersion. Cropped vertisols displayed the higher amount of water dispersible clay while not cropped recorded the smaller amount. Concerning the cropped soils, irrigated vertisols displayed the highest clay dispersion indices suggesting that agricultural practices (irrigation) enhance clay dispersion. Globally, the clay dispersibility trend was: irrigated paddy ? rainy sorghum ? rainfed paddy ? dry-season sorghum ? not cropped. Statistical analyses revealed that amorphous Al, Na+ and electrical conductivity enhance clay dispersion while organic matter, nitrogen and Ca++ promote clay flocculation/aggregation. The overall findings emphasized that practices such as heavy tillage and irrigation induce clay dispersion. Minimum tillage, electrolytes concentration monitoring in irrigation water, irrigation scheduling based on soil moisture control, organic matter inputs and implementation of adapted dams are measures susceptible to limit their degradation through clay dispersion.

关键词： Vertisols Clay dispersion Irrigation Land use North Cameroon

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Ethics of Human Resources Management in the Cameroonian Health System, Medical Nomadism and the Ineffectiveness of the Fight against High Blood Pressure

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Health 2024年第1期16卷 9-21页

作者： Jean Ndibi Abanda Anicet Onana Akoa désiré Tchoffo Ulrich dama Pierre Yassa Yoniene Faculty of Health Sciences University of Lisala (CIREP-UNILIS) Lisala Democratic Republic of the Congo National Order of Medical and Sanitary Professions Yaounde Cameroon School of Health Sciences Catholic University of Central Africa Yaounde Cameroon World Health Organization Maroua Cameroon Faculty of Medicine University Simon Kimbangu Kinshasa Democratic Republic of the Congo

Context/objectives: The fight against Chronic Non-Communicable diseases (NCds) is a long-term undertaking, which requires available, motivated and well-managed human resources (HR). The administrative management of skills on both qualitative and quantitative levels is one of the essential functions of a health system. To better implement policies of fight against High Blood Pressure (HBP) and other chronic diseases, it is important to establish strategies to retain health personnel. This loyalty requires favorable working conditions and consideration of the contribution-reward couple. Good working conditions are likely to reduce the phenomenon of medical nomadism;conversely, poor HR management can contribute to their exodus towards exotic “green pastures”, thus leading to an additional crisis in the Cameroonian health system. The fight against HBP is a complex, multifaceted and multifactorial reality that requires appropriate management model for all types of resources mainly HR. The main objective of this research is to show the impact of poor management of human resources in Cameroon health system on medical nomadism and the ineffectiveness of the fight against High Blood Pressure. Method: A cross-sectional descriptive survey among five hundred (500) health facilities in the center region of Cameroon has been conducted. A stratified probabilistic technique has been used, and the number of health facilities to be surveyed has been determined using the “sample size estimation table” of depelteau. The physical questionnaires have been printed and then distributed to data collectors. After data collection, the latter were grouped during processing in Excel sheets. The Chi-square test was used for data with a qualitative value and that of Kolmogorov-Sminorf for data with a quantitative value to assess the normality and reliability of data. The Crochach’s Alpha reliability test allowed us to have a summary of the means and variances and then to search for intragroup cor

关键词： Ethics Human Resources Management Cameroonian Health System Medical Nomadism Ineffectiveness High Blood Pressure

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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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Coordination of Regulation devices for damping Power Oscillations in a dynamic disturbance Context: A Fuzzy Logic-Based Approach Applied to the Electrical Grid of the Republic of Congo

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Journal of Power and Energy Engineering 2024年第1期12卷 44-60页

作者： Mavie Grace Mimiesse davy Rostand Souamy Loembe Smaël Magloire Elombo Motoula désiré Lilongo-Boyenga Laboratoire du Génie É lectrique et &#201lectronique &#201cole Nationale Supérieure Polytechnique Université Marien NGOUABI Brazzaville Congo Institut Supérieur d’Architecture Urbanisme Batiment et Travaux Punlics Université Dénis SASSOU-N’GUESSO Kintelé Congo

This article presents a fuzzy logic-based approach to coordinate the control devices of the power system, such as Power System Stabilizers (PSS) and Static Synchronous Compensators (STATCOM), to damp power oscillations caused by dynamic disturbances. At first, we used the Lyapunov method to study the dynamic stability of the power grid in the Republic of Congo. This method allowed us to analyze the eigenvalues of the state variable matrix and highlight the eigenvalues in the complex plane. Secondly, we proposed a fuzzy logic-based controller to account for uncertainties existing near the thresholds. The inputs to this controller are the generator speed and generator rotor angle. We demonstrated the effectiveness and feasibility of this fuzzy control by applying it to the power grid of the Republic of Congo, with three power stabilizers and two STATCOMs. .

关键词： Fuzzy Logic STATCOM PSS Lyapunov Republic of Congo

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Mobility of Major and Trace Elements during the Bauxitization Processes in Ngaoundal Area (Adamawa Cameroon): Implication on Mining Perspectives

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Open Journal of Geology 2024年第1期14卷 81-100页

作者： André Sini Harouna Boukari Ondoa Augustin désiré Balla djetenbe Beral Salomon Wangmené Awé Simon djakba Basga Jean Pierre Nguetnkam department of Mining Engineering School of Geology and Mining Engineering University of Ngaoundere Ngaoundere Cameroon department of Mining Engineering and Environment School of Mining Industry and Geology University of Abdou-Moumouni Niamey Niger department of Earth Sciences Faculty of Science University of Ngaoundere Ngaoundere Cameroon department of Mining Engineering Saint Jerome Polytechnic Saint Jerome Catholic University Institute of Douala Douala Cameroon Institute of Agricultural Research for development (IRAd) Garoua Cameroon

This study was focused to assess major and trace elements in bauxitic duricrusts from Ngaoundal and its surroundings in order to establish their mining interest. To this end, fieldworks, mineralogical and geochemical analyses were carried out. Four facies of duricrust were identified and characterized from the summit to the top of the slope of the Ngaoundal mountain: scoriaceous, pisolitic, nodular and massive. Mineralogical and geochemical analyses performed on 16 samples, revealed a significant concentration of Al2O3 mainly in the scoriaceous facies (over 45% in grade), moderate in Fe2O3 (averaging 23.69%) and SiO2 (averaging 21.7%). Trace elements were generally low, excluding Cr (421 ppm on average), Zr (327 ppm on average and V (213 ppm on average). In addition, the limited quantities of alkalis (Na2O, K2O) and alkaline earths metals (MgO, CaO) coupled with the very high values of Chemical Index of Alteration (CIA) and Mineralogical Index of Alteration (MIA), (more than 99%) attest to the intense weathering of the studied materials. Allitization and monosiallitization constituted the crystallochemical phenomena that have led to the development of bauxitic minerals. More than 90% of gibbsite in scoriaceous facies, 52.21% - 76.01% of kaolinite in pisolitic facies and more than 40% of hematite in nodular facies were quantified. The relationships between the constitutive components indicated their interdependency during the bauxitization phenomenon. The mineralogical and geochemical properties highlighted the mining interest of the studied duricrusts to be valorized.

关键词： duricrust Bauxitization Phenomenon Mineralogical and Geochemical Characterization Major and Trace Elements Mining Potential

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Relevance of Medical Imaging in the Pre-Therapeutic Evaluation of Acute Intestinal Obstruction at CIMEd

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Open Journal of Medical Imaging 2024年第1期14卷 31-41页

作者： Mamoudou Camara Aly Mampan Koundouno siré Nabe Toumin Camara Ousmane Aminata Bah Center for Medical Imaging Exploration and Diagnostics University of Conakry Conakry Guinea General Surgery department of the Kankan Regional Hospital Kankan Guinea Ministry of Health and Public Hygiene Conakry Guinea General Medicine department of the Siguiri Prefectural Hospital Siguiri Guinea CIRA Conakry Guinea

Objective: We initiated this work with the aim of studying the contribution of imaging in the diagnosis of acute intestinal obstruction at CIMEd. Patients and methods: This was a prospective, descriptive and analytical study involving 96 patients collected at the radiology and medical imaging department of CIMEd, from January 2022 to January 2023. Result: The age of our patients varied between 11 and 86 years with an average age of 36 years. There was a male predominance of 64.6% compared to 35.4% for women, i.e. a sex ratio of 1.82. The notion of previous surgery was found in 61.5% of our patients. Pain was present in all patients. Radiography of the ASP was performed in 89.6% of patients. It showed hydro-aerial levels in 96.5% of patients. Abdominopelvic CT was performed in 12 patients and made it possible to make the diagnosis of occlusion in all patients. The results of the positive diagnosis were concordant with those intraoperatively in 92% of cases. 8% of our patients, compared to the treatment, spontaneously resumed their transit, 91% benefited from surgical treatment and 1% died before surgery. The outcome was favorable in 80 patients or 83.3%, poor with death in 16 patients or 16.7% of cases. Conclusion: Acute intestinal obstruction remains a serious pathology for which ASP radiography often remains the only radiological examination performed urgently. However, abdominopelvic CT seems widely indicated thanks to its contribution both for the positive diagnosis and for the serious and etiological diagnoses. However, this imaging technique is largely underused in our practice due to its high cost and lack of availability.

关键词： Imaging Acute Intestinal Obstruction CIMEd

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Insight of Natural Compounds Halimane diterpenoids against Mycobacterium tuberculosis: Virtual Screening, dFT, drug-Likeness, and Molecular dynamics Approach

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Computational Molecular Bioscience 2024年第2期14卷 35-58页

作者： Laurent Gael Eyia Andiga Boris davy Bekono désiré Mama Bikele Pie Pascal Onguéné Amoa Luc Calvin Owono Owono Luc Léonard Mbaze Meva’a department of Chemistry Faculty of Science University of Douala Douala Cameroon department of Physics Ecole Normale Suprieure University of Yaound 1 Yaound Cameroon Center for drug discovery Faculty of Science University of Buea Buea Cameroon department of Chemistry University of Yaound I Institute of Wood Technology Mbalmayo Cameroon CEPAMOQ Faculty of Science University of Douala Douala Cameroon

In the purpose to design novel antituberculosis (anti-TB) drugs agents against Mycobacterium tuberculosis (Mtb), we have built a molecular library around 42 Halimane diterpenoids isolated from natural sources. Two Mtb enzymes drug targets (Mtb Mycothiol S-transferase and Mtb Homoserine transacetylase) have been adopted. The pharmacological potential was investigated through molecular docking, molecular dynamics simulation, density functional theory (gas phase and water) and AdMET analysis. Our results indicate that (2R,5R,6S)-1,2,3,4,5,6,7,8-octahydro-5-((E)-5-hydroxy-3-methylpent-3-enyl)-1,1,5,6-tetramethylnaphtha-lene-2-ol (compound 20) has displays higher docking score with each of the selected drug targets. In addition, this molecule exhibits a satisfactory drug potential activity and a good chemical reactivity. Its improved kinetic stability in the Mtb Mycothiol S-transferase enzyme reflects its suitability as a novel inhibitor of Mtb growth. This molecule has displayed a good absorption potential. Our results also show that its passive passage of the intestinal permeability barrier is more effective than that of first-line treatments (ethambutol, isoniazid). In the same way, this anti-TB druglikeness has shown to be able to cross the blood brain barrier.

关键词： Antituberculosis druglikeness density Functional Theory Halimane diterpenoids Molecular docking Molecular dynamics Simulation

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Economic Stress, Precariousness and Risk of High Blood Pressure: A descriptive Survey of Life Models within Households of the Central Region of Cameroon

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Health 2024年第2期16卷 118-130页

作者： Jean Ndibi Abanda Ulrich dama Viviane Foussouo Ndoungue Anicet Onana Akoa Melkior Fobasso dzeuta Alphonse Tedonge Asobochia Arsène Emilien Messi Ndzengue désiré Tchoffo Faculty of Health Sciences University of Lisala (CIREP-UNILIS) Lisala Democratic Republic of the Congo National Order of Medical and Sanitary Professions Yaoundé Cameroon School of Health Sciences Catholic University of Central Africa Yaoundé Cameroon World Health Organization Maroua Cameroon Faculty of Health Sciences University of Montagnes Banganté Cameroun Faculty of Medicine University of Bamenda Bamenda Cameroon Faculty of Sciences University of Ebolowa Ebolowa Cameroun

Context/Objective: High blood pressure (HBP) currently represents the most widespread chronic non-communicable disease in Cameroon. The increase in its prevalence in the country is the result of multiple factors including economic stress imposed by precariousness, poor living conditions, sources of anxiety, anguish, depression and other behavioral disorders. Economic stress is a globalizing concept that integrates into a purely hermeneutic approach, a particular functioning of the nervous system of an individual who faces employment problems and precarious remuneration conditions. The non-satisfaction by an individual of his basic needs due to insufficient financial means can cause him to become irritable, aggressive, and socially and symbolically isolated, thereby increasing the desire to resort to morbid life models such as excessive consumption of narcotics and other psychoactive substances often associated with high blood pressure. The fight against the emergence of BPH is a complex, multifaceted and multifactorial reality that requires taking into account economic stress. The main objective of this survey is to describe the situation of economic stress within the Cameroonian population, which imposes precariousness and life models at risk of high blood pressure. Specifically, we determined the level of household income and the sources of income. Methods: A cross-sectional survey with a descriptive aim among five hundred households in the Central Region of Cameroon was conducted. A probabilistic technique called simple randomness was used. The number of households to be surveyed was determined indirectly using the Cochrane formula. data collection in face-to-face mode using a physical questionnaire took place from July 1 to August 31, 2023, after obtaining ethical clearance from the Regional Health Research Ethics Committee, Human from the Center and an administrative authorization for data collection. Regarding their processing, the data was grouped during proc

关键词： Economic Stress Precariousness High Blood Pressure Life Models Households

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Watson-Jones Anatomical Approach for Open Reduction and Internal Fixation of Proximal Femoral Fractures without Image Intensifier in a Low-Resource Setting

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Open Journal of Orthopedics 2024年第4期14卷 173-186页

作者： Loïc Fonkoue Gaspary Fodjeu Kennedy Olivier Muluem Olivier Ngongang Theophile Nana Marie Ange Ngo Yamben désiréAkaba Urich Tambekou daniel Eone Handy department of Orthopaedics and Trauma Yaound&#233 General Hospital Yaound&#233 Cameroon. department of Surgery and Specialities University of Yaound&#233 1 Yaound&#233 Cameroon department of Orthopaedics and Trauma Yaound&#233 Emergency Center Yaound&#233 Cameroon department of Orthopaedics and Trauma Yaound&#233 Central Hospital Yaound&#233 Cameroon

Introduction: Standard procedures for surgical fixation of proximal femoral fractures (PFF) require an image intensifier which in developing countries remains a luxury. We hypothesized that, with a well-codified technique, the Watson Jones approach (WJA) without image intensifier nor traction table, can allow open reduction and internal fixation (ORIF) of PFF using dynamic hip screw (dHS), with satisfactory outcome. Patients and methods: Forty one consecutive patients (mean age 59.5 ± 21.6 years, 61% males) who were followed in a Teaching Hospital for PFF treated by ORIF using the WJA and dHS from January 2016 to december 2020 were reassessed. The outcome measures were the quality of the reduction, the positioning of the implants, the tip-apex distance (TAd), the rate and delay of consolidation, the functional results using Postel Merle d’Aubigné (PMA) score, the rate of surgical site infection (SSI) and the overall mortality. Logistic regression was used to determine factors associated with mechanical failure. Results: The mean follow-up period was 33.8 ± 15.0 months. Fracture reduction was good in 31 (75.6%) cases and acceptable in 8(19.5%) cases. Implant position was fair to good in 37 (90.2%) patients. The mean TAd was 26.1 ± 3.9 mm. Three patients developed SSI. Consolidation was achieved in 38 (92.6%) patients. The functional results were good to excellent in 80.5% of patients. The overall mortality rate was 7.3%. There were an association between mechanical failure and osteoporosis (p = 0.04), fracture reduction (p = 0.003), and TAd (p = 0.025). In multivariate logistic regression, no independent factors were predictive of mechanical failure. Conclusion: This study shows that ORIF using dHS for PFF via the Watson-Jones approach without an image intensifier can give satisfactory anatomical and functional outcomes in low-resource settings. It provides and validates a reliable and reproducible technique that deserves to be diffused to surgeons in austere areas o

关键词： Proximal Femoral Fracture Watson-Jones Approach dynamic Hip Screw Low Resource Setting

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Perception of the Mechanization of Rice Cultivation and Its Effects on the Soil in the Senegal River Valley

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Agricultural Sciences 2024年第6期15卷 704-718页

作者： Cheick Atab Mane siré diedhiou Arfang Ousmane Kémo Goudiaby Mohamed Sall Guillaume Gillet Machinery and Renewable Energy department University of Sine Saloum El Hadji Ibrahima NIASS Kaolack Senegal Agroforestry department Assane Seck University Ziguinchor Senegal department of Agronomy Vegetable Production University of Sine Saloum El Hadji Ibrahima NIASS Kaolack Senegal National Training School for Agricultural Education Toulouse France

In Senegal, particularly in the Senegal River valley, agricultural mechanization remains limited, mainly due to a lack of agricultural equipment, a lack of expertise in agricultural machinery and an apprehension of the consequences on soil quality. To better understand agricultural mechanization of rice cultivation, this survey study has been carried out in the Senegal river valley. Precisely, this work aimed to characterize farm machinery and its effects on soil and rice cultivation. A questionnaire was administered to 304 out of 1270 farmers, spread over 8 rice-growing areas, 4 of which are located in the Podor department, three in dagana and one in Saint-Louis. The results showed that 99.3% of farmers used motorized equipment, with 95.7% using tractor and 3.6% a power tiller. Offset tillage, which is a shallow cultivation practice carried out to break up hard soil without turning it over, was most widespread among growers (95.4%). 78.3% of the valley’s farmers felt that the machinery used to carry out tillage operations was inefficient. According to the farmers, the main constraints on the use of agricultural machinery in the valley were: the upkeep and maintenance of equipment (57%), the lack of expertise in mechanization (31%), and issues adapting machinery to local conditions (12%). Those constraints have contributed to a drop in yields in recent years, the spread of weeds on cultivated plots and the gradual degradation of the soil in the area according to 78% of farmers.

关键词： Agricultural Mechanization Characterization Constraints Soil Rice

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