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Source of metals related to gold occurrences in cameroon, Central African Belt

Acta Geochimica 2024年第2期43卷 308-324页

作者： Kevin Igor Azeuda Ndonfack Jinlin Zhang Yuling Xie NSamiratou Yaya Emmanuel Archelaus Afanga Basua JCHX Mining Management Co. LtdBeijing 101500People’s Republic of China Institute of Geology Chinese Academy of Geological SciencesBeijing 100037People’s Republic of China School of Civil and Environmental Engineering University of Science and Technology BeijingBeijing 100083People’s Republic of China Department of Earth Science University of BamendaBamendaRepublic of Cameroon

Suites of granitic and metamorphic rocks form a perfect geological environment in which to investigate the source of metals related to gold *** the East Province of cameroon,the source of metals-related gold(grade~4.6 g/t)that occurs within metamorphic and granitic rocks remains *** host rocks were subjected to XRF and ICP-MS whole-rock geochemistry and BSE/EDS mineral analyses to investigate the source(s)of metals related to gold in the ***,chalcopyrite-pyrite and magnetite-ilmenite are the main sulfi des and oxides of granites,*** low-grade metamorphic rocks are sulfi de-rich consisting of arsenopyrite,chalcopyrite,pyrite,and sphalerite,and oxides include magnetite,ilmenite,hematite,and ***,Ni,Co,Sb,Sc,and Zn concentrations depleted in high-grade metamorphic rocks and granites compared to low-grade metamorphic *** well,Bi,Cd,Co,Cu,Ni,Sb,V,W,and Zn concentrations decrease with increasing temperatures from low-grade rocks to high-grade rocks and *** suite of depleted elements in high-grade rocks and granites is almost identical to those enriched in gold *** conclude that metals(Bi,Cd,Co,Cu,Ni,Sb,and Zn)related to gold mineralization in the East Province of cameroon likely originated from metal-rich low-grade metamorphic rocks during prograde metamorphic processes prior to partial melting.

关键词： East Province of cameroon Metamorphic rocks Granites Oxide–sulﬁdes Metal and gold Geochemistry

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Tree Population Dynamics of Three Altitudinal Vegetation Communities on Mount cameroon(1989-2004)

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Journal of Mountain Science 2011年第4期8卷 495-504页

作者： Philip F.FORBOSEH Terry C.H.SUNDERLAND James A.COMISKEY Michael BALINGA plan cameroon P O Box 25236 MessaYaoundéCameroon Centre for International Forestry Research(CIFOR) Inventory and Monitoring Program National Park Service120 Chatham Lane Smithsonian Institution S.Dillon Ripley Center1100 JeffersonDrive SW Washington DC 20560USA Center for International Forestry Research(CIFOR)

Changes in permanent sample plots in the lowland,submontane and montane forests on Mount cameroon(4,095 m above sea level),an active volcano,are described for 15 years from 1989 to *** the study period,the stocking level of trees with a diameter at breast height(DBH) ≥ 10 cm in the three forests were lower than in pan-tropical stands suggesting a significant impact of volcanic and human-related activities on the vegetation communities on the *** mortality rates in the submontane and montane forests were consistent with those reported for comparable altitudinal ranges in the Blue Mountains of *** annual mortality rate was higher in the lowland forest than other lowland sites *** between recruitment and mortality rates was large suggesting that the three vegetation communities have not reached their *** seven-year difference in half-life of large trees(with a DBH ≥ 50 cm) in the submontane and montane forests suggests an altitudinal effect on turnover of larger trees that in turn contributes to the frequent small stature of high altitude *** was little evidence of an altitudinal effect on species turnover and growth *** finding supports generalizations about the zero effect of growth on the stature of high altitude *** forest dynamics is crucially important in the management of tropical montane environmentsand in this instance particularly so given the recent creation of the Mount cameroon National Park.

关键词：植被群落高海拔喀麦隆活火山种群动态山地森林树木胸径热带山地

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Acute and Chronic Pain: Best Management Approaches in Resource Limited Setting, cameroon

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Pain Studies and Treatment 2022年第1期10卷 1-8页

作者： Njumbo Petronilla Balgah Mary Bi Suh Atanga Department Nursing University of Bamenda Bamenda Cameroon

Pain is a common event in many scenarios involving healthcare, from birth to death, in the hospital or outside of it. The overall purpose of this work was to critically review articles on types of pain and options employed in managing pain. Some electronic sources like google scholar, Ovid MEDLINE, PsychINFO, Embase were used to source for information. The articles were reviewed according to the various themes of the topic. From the different sources pain is categorized as acute or chronic with physical, psychological and social characteristics. Effective management of pain utilizes both pharmacologic and non-pharmacologic therapy. Pharmacological therapy employs non-opioids medications. Prolonged or unnecessary use of opioids causes some harmful side effects to the patient. Non-pharmacologic therapy plays a significant role and should be included in the multidisciplinary treatment plan. Nurses are members of the healthcare team who spend most of their time with patients as such they must work in collaboration with other healthcare professionals to facilitate patient’s recovery from pain. Healthcare professionals should also make use of internationally recognized guidelines during practice.

关键词： Acute Chronic Pain Management

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Quantifying Forest Loss in the Mbalmayo Forest Reserve (Center Region, cameroon)

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Journal of Geoscience and Environment Protection 2022年第9期10卷 271-288页

作者： Mingang Danielle Liliane Ngueguim Jules Romain Momo Solefack Marie Caroline Tchongouang Abigaelle Tientcheu Tcheugoue Alphonse Loic Unité de Recherche de Botanique Appliquée (URBOA) Department of Plant Biology Faculty of Science University of Dschang Dschang Cameroon Agricultural Research Institute for Development (IRAD) Yaoundé Cameroon Department of Geography Faculty of Letters and Humanities University of Dschang Dschang Cameroon Department of Geography Faculty of Arts Letters and Humanities University of Yaoundé I Yaoundé Cameroon

This study was carried out in the forest reserve of Mbalmayo, Center Region of cameroon, with the aim to analyze the dynamics of land use/land cover (LULC) changes over the past 30 years. The databases used were made up of 3 Landsat satellite images (5TM of 1990, 7ETM+ of 2005 and 8OLI of 2020). The satellite images were processed using ArcGIS and Erdas Imagine software. Ethnobotanical surveys were conducted to investigate the relationships between the local population and the forest reserve. The Mbalmayo forest reserve is consisted of seven main land cover namely: mature secondary forest, young secondary forest, savanna, fallows and crops, built, bare soil and water surface. The dynamics of the forest cover undergoes more significant changes between the years 1990-2005 with losses estimate at 4762 ha compared to the years 2005-2020 (2231 ha), with a marked decrease in the area of dense forests. This regression is much more important in dense forest vegetation. The forest cover lost 6993 ha (26.92%) of its surface, which corresponds to an average rate of deforestation of 233.1 ha/year. The survey revealed the need for NTFPs for the Mbalmayo reserve forest populations. Indeed, all respondents agreed that they use non-timber forest products from the forest, mainly for medication (37%), wood (34%) and food (24%). Therefore, it becomes urgent to redefine a management plan for the Mbalmayo forest reserve which will define how the forest must be managed in order to avoid the loss of large areas of forests disappearing each year under the human action, which exerts pressure on forest species, thus leading to their possible disappearance.

关键词： Mbalmayo Forest Reserve Satellite Images Ethnobotany Land Use/Land Cover Change

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Major Ear Aplasia and Cochleovestibular Dysplasia: Rare Congenital Malformation about a Case

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International Journal of Otolaryngology and Head & Neck Surgery 2023年第6期12卷 397-404页

作者： Mouangue-Mbonjo Louise Epée Ngoué Jeannette Mantho Fopa Pauline Njifou Njimah Amadou Faculty of Medicine and Pharmaceutical Sciences (FMSP) Department of Surgery and Specialties University of Douala Douala Cameroon ENT and Maxillofacial Surgery Department Yaoundé Central Hospital Yaoundé Cameroon Department of Pediatrics Faculty of Medicine and Biomedical Sciences University of Yaoundé I Yaoundé Cameroon

Introduction: The congenital malformations of the ear are rare and often isolated, may be unilateral or bilateral, and can be associated with another syndromic malformation. Such malformations so not necessarily impact aesthetics and social relations. Case Presentation: The authors report the case of Samuel M, male born at 38 WA, who is the first child of healthy parents from the same socio-cultural area. His birth weight was 2800 g and he did not have any risk factors for deafness or concept of obstetrical trauma. He presented with congenital malformation manifesting as bilateral ear aplasia with unilateral facial paralysis. Computed tomography revealed abnormalities of the inner ear;functional explorations, such as PEA and OEA, showed findings in favor of bilateral cophosis. ASSR (Auditory Steady-State Responses) was not performed. The announcement of the serious diagnosis of deafness requires multidisciplinary care in order to plan a therapeutic program to limit the impact on the development of language, schooling, and consequently, the socio-professional future of children. Conclusion: This clinical case underlines the fact that interest of the clinical interview before possible multiple surgery does not always guarantee the satisfaction of the desire for repair in this type of patient.

关键词： Ear Malformations Congenital Malformations Major Aplasia Congenital Facial Paralysis Congenital Deaf-Mutism

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Local Perception of Climate Change and Adaptation in Mangrove Areas of the cameroon Coast

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Journal of Water Resource and Protection 2016年第5期8卷 608-618页

作者： Ndongo Din Vanessa Maxemilie Ngo-Massou Guillaume Léopold Essomè-Koum Ernest Kottè-Mapoko Jean Michel Emane Akusa Dorice Akongnwi Richelieu Tchoffo Department of Botany Faculty of Science The University of Douala Douala Cameroon Technical Assistance Unit Environmental and Social Management Plan of the Mefou Watershed Cameroon Water Utilities Corporation Project Douala Cameroon Department of Biological Sciences High Teacher’s Training College The University of Yaounde I Yaounde Cameroon

Mangroves supply essential ecosystem services to tropical informal economies. In the cameroon coastal region, the impacts of various projections on change in temperatures and precipitations sound low compared to the pressure of human activities. This survey evaluated the sensitivity of local population on the impact of climate change and the vulnerability of coastal ecosystems. An investigation carried out on 425 individuals was based on the major income and development activities, the knowledge of the subject, the information sources, the origin of changes, perceptible effects, risks and consequences. More than 90% of interviewees have heard about climate change essentially from radio (20%). Industries (47.53%) are perceived to have major responsibility for temperature (78%) and precipitation (67%) changes and increased inundation (39.07%) was perceived as the highest risk. Compared with Cartesian predictions in the area, the results have shown the sensitivity of population to local variation of climate factors. No efficient endogenous measure has been recorded. Forest and specially mangroves are the most affected ecosystems by local activities. Expected extension of the dry season could affect the natural regeneration and the structure of mangrove forests. Considering the importance of woody species in the local economies, the lack of appropriate actions and adaptation measures will lead to the total degradation of mangroves.

关键词： Anthropogenic Activities Investigation Prediction Risks Vulnerability

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Towards an Eco-Efficient Development Strategy that Minimises the Risks Associated with the Location of Gas Stations in Human Settlements: A Fuzzy PROMETHEE Method

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World Journal of Engineering and Technology 2022年第1期10卷 119-137页

作者： Samuel Batambock Innocent Ndoh Mbue Dieudonne Bitondo Laboratoire de Recherche Energie Matériaux Modélisation et Méthode (E3M) Douala Cameroon Ecole Nationale Supérieure Polytechnique de Douala (ENSPD) Université de Douala Douala Cameroon

Evaluating real world situations in risky environments based on various qualitative/quantitative criteria in order to suggest a strategy/policy among available options is one of the critical challenges in incident management. Such is the case when considering an eco-efficient development strategy that can minimize the risk associated with the location of gas stations in human settlements. Taking the Douala city of cameroon as an example, four actions were evaluated, including the options of relocating the gas stations, putting in place of emergency response plan in gas stations, and relocation of households subject to a group of four criteria. Data were collected via personal communication with decision-makers using a five-point Likert scale. The market values of buildings subject to expropriation were estimated based on order No. 0082/Y. 15.1/MNUH/D of 20 November 1987 of the ministry of Housing and Urban Development, cameroon. The financial costs incurred in establishing a gas station were an average value obtained from a sample of 80 gas stations randomly selected among those whose locations do not comply with existing regulations. These amounts were obtained from their financial records, while the value of putting in place an emergency action plan was obtained from the current market value of the equipment required. The algorithm of PROMETHEE under the usual criterion function was implemented. The results suggested that putting in place an emergency response plan could minimize relocation costs, maximize profits/welfare, and maximize environmental quality, and minimize social impacts, and was therefore considered as the most preferred alternative. Sensitivity analyses of results further confirmed that implementation of emergency response plan is the most preferred alternative.

关键词： Eco-Efficient Development Strategy PROMETHEE Criteria Alternatives

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Contribution for Efficient planning of Millimeter Wave Frequencies: Case of the 80 GHz E-Band for High-Speed Broadband Transmissions

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Journal of Computer and Communications 2023年第11期11卷 111-148页

作者： Patrick Dany Bavoua Kenfack Alphonse Binele Abana Emmanuel Tonye Paul-Salomon Ngohe-Ekam Jacques Nyemb Nga Department of Electrical and Telecommunications Engineering National Advanced School of Engineering of Yaounde University of Yaounde I Yaounde Cameroon

Due to the very high demand for Internet data capacity from mobile and fixed customers as well as the saturation of conventional frequency bands by numerous services, many countries have opened the E band, for broadcasting services. E-band involves the creation of a significant number of links in a given area. The present work addressed the problem that arises in the context of transmission is that of assigning the frequencies of this band to these multiple transmission links. The aim of this work is to study and plan the radio links of the 80 GHz frequency and to implement them in a tool in order to define an optimal distribution on the telecommunications network by guaranteeing maximum flow of data traffic while minimizing the interference. The contribution of this work is part of its unique subject: the planning of E-band frequencies for improving the quality of service of transmission in the network of telecommunications operators. Also, it intends to contribute to the resolution of unsatisfied situations of poor planning of E-band radio frequencies in telecommunications networks. With the aim of opening several opportunities for alternative high-speed data transport solutions, our work has helped prove that E-band transmission links are very efficient with capacities in the gigabyte range.

关键词： Radio Beams E-Band Frequency planning Microwave

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The Role of Community-Based Ecotourism in Biodiversity Conservation in the Mount Oku Area, cameroon

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Journal of Geoscience and Environment Protection 2023年第12期11卷 132-150页

作者： Jicenta N. Foncha Assonwa E. Fouomene Department of Development Studies Pan African Institute for Development-West Africa (PAID-WA) Buea Buea Cameroon

Forests are biodiversity hotspots which provide livelihood and act as safety nets for adjacent communities. Increasing dependence on forest is threatening this biodiversity. Ecotourism, a biodiversity conservation strategy has the potential to restore degraded habitat, and create socio-cultural and economic benefits that improve communities’ livelihoods. This study focused on the role of community-based ecotourism in biodiversity conservation in the Mount Oku forest, of the North West region of cameroon. The study identified and ranked livelihood activities that led to biodiversity destruction, assessed ecotourism potentials and conservation practices, identified ecotourism benefits and assessed household income levels before and after the institution of ecotourism. We randomly selected three communities from the study area. The study was guided by the Forest Management plan, the Simple Management plan of the Kilum/Ijim forest project and the concept of Biosphere Reservation. Descriptive statistics were simple percentages presented on tables, while the inferential statistics of Wilcoxon rank test was used to analyze the data collected for the study. Our findings reveal that, the livelihood activities that led to biodiversity destruction include agriculture, logging, fuelwood collection and grazing. Ecotourism potentials/conservation strategies were nature-based, education-based, culture-based, and agriculture-based;value chain was integrated in all these aspects which enhanced livelihood diversification. The benefits include business opportunities, infrastructure development, and forest regeneration. Income level generated after the institution of ecotourism was higher than the level of income before (Z = -1442, p = 0.001). Clear indicators need to be established to measure long-term project effectiveness in biodiversity conservation and livelihood sustainability.

关键词： Conservation Community Involvement Cultural Heritage Livelihood Diversification Value-Chain

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Empirical Models for the Evaluation of Global Solar Radiation for the Site of Abeche in the Province of Ouaddaï, in Chad

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Smart Grid and Renewable Energy 2022年第10期13卷 223-234页

作者： Marcel Hamda Soulouknga Abraham Dandoussou Noel Djongyang Higher Normal School of Technical Education of Sarh University of Sarh Sarh Chad Department of Electrical and Power Engineering Higher Technical Teachers’ Training School University of Buea Kumba Cameroon Department of Renewable Energy National Advanced Polytechnic School University of Maroua Maroua Cameroon

The global sustainability plan for future development relies on solar radiation which is the main source of renewable energy. Thus, this work studies the performance of six models to estimate global solar radiation on a horizontal surface for the Abeche site in Chad. The data used in this work were collected at the General Directorate of National Meteorology of Chad. The reliability and accuracy of different models for estimating global solar radiation were validated by statistical indicators to identify the most accurate model. The results show that among all the models, the Sabbagh model has the best performance in estimating the global solar radiation. The average is 6.354 kWh/m2 with an average of -3.704%. This model is validated against NASA data which is widely used.

关键词： Empirical Models Statistical Indicators Solar Radiation Abeche

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