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Characterization of Sediment from Ourokessoum, North Cameroon: Morphostructural, Mineralogical, and Physicochemical Properties

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Journal of Geoscience and Environment Protection 2024年第9期12卷 51-76页

作者： Atangana Jacqueline Ntsama Kadaguina Doussana Joseph Roland Atenga Essama Akoa Philémon Rémi Etoundi Bilobi Roland Touna jean pierre nguetnkam Department of Earth Sciences Faculty of Science University of Yaound I Yaound Cameroon Department of Earth Sciences Faculty of Science University of Ngaoundere Ngaoundr Cameroon College of Civil Engineering and Architecture China Three Gorges University Yichang China Department of Mining Geology School of Geology and Mining Engineering University of Ngaoundere Meiganga Cameroon

The present study examines the morphological, physicochemical, and mineralogical specificity of clay sediments in the Hamakoussou Basin with the objective of exploring their potential applications. Field data collection was followed by a series of physicochemical and mineralogical tests on the clay samples. Results show that the clay layers, which range in thickness from 11 - 120 cm, exhibit gray, yellowish, or greenish colors. From a physicochemical perspective, these clay layers are found to be basic with a pH ranging from 8.5 for the higher Hama2 layer to 7.6 for the lower Hama1 layer. The sum of exchangeable bases (S) is medium to high with higher values in the Hama1 layer (53.45 meq/100g) and lower values in the Hama3 layer (17.09 meq/100g). Similarly, the cation exchange capacity (CEC) varies from 62.32 meq/100g for the higher Hama1N4 clay layer to 35.6 meq/100g for the lower Hama1N3 clay layer. Mineralogically, the clay materials are primarily composed of smectites, with illite, kaolinite, calcite, quartz, feldspar, hematite, and goethite also present. This study emphasizes the versatility of clay in various industries and scientific domains. It is known for its impermeability, plasticity, and fossil-preserving capabilities, making it a valuable material for economic, practical, and academic applications.

关键词： Morphostructural Sediments Clay Layers Sedimentary Basin Hamakoussou

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

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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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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（地质学期刊） 2024年第1期

作者： André Sini Harouna Boukari Ondoa Augustin Désiré Balla Djetenbe Beral Salomon Wangmené Awé Simon Djakba Basga jean pierre nguetnkam

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Variation of Soils Erodibility in Mbe Agropastoral Area in Relation with Land Utilization, Central Cameroon

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Open Journal of Soil Science 2019年第12期9卷 269-283页

作者： Boukar Atougour Simon Djakba Basga Elisabeth Yaboki jean pierre Temga jean pierre nguetnkam Department of Earth Sciences Faculty of Science University of Ngaoundéré Ngaoundéré Cameroon Institute of Agricultural Research for Development (IRAD) Garoua Cameroon Institute of Agricultural Research for Development (IRAD) Ngaounderé Cameroon Department of Earth Sciences Faculty of Science University of Yaoundé I Yaoundé Cameroon

The study of the soils from Mbé and Wack is carried out in the framework of the knowledge of soils from the Adamawa Region of Cameroon and their erodibility was investigated using erodibility indices obtained through physico-chemical data. Eleven topsoils (0 - 20 cm) samples were collected on different land use and their susceptibility to erosion was assessed. The water dispersible clay (34.92 - 121.75 g•kg−1), the clay dispersion ratio (0.45 - 0.84) and the dispersion ratio (0.75 - 0.89) were high in the studied soils while the clay aggregation (13.16 - 42.27g•kg−1) and the clay flocculation index (0.16 - 0.55) were low to moderate indicating their high erodibility. The soils under natural vegetation, more clayey, displayed the highest amount of water dispersible clay while cropped soils recorded the smaller ones. Globally, in cropped soils, those under cereals displayed the highest clay dispersion indices than those under tubers. This suggests that tubers cropping practices in studied soils enhance their erodibility. Statistical analyses revealed that amorphous Al and Fe are elements which limit soils erodibility while K+ and promote soils particles dispersion. Sustainable management of these soils will consist on limiting runoff through agricultural practices such as direct seedling and orienting tillage perpendicularly to slope gradient.

关键词： Mbé Wack Erodibility Soil Properties Land Use

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Monitoring absolute vertical land motions and absolute sea-level changes from GPS and tide gauges data over French Polynesia

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Geodesy and Geodynamics 2024年第1期15卷 13-26页

作者： Xianjie Li jean-pierre Barriot Bernard Ducarme Marania Hopuare Yidong Lou Geodesy Observatory of Tahiti University of French PolynesiaFaa'a 98702French Polynesia Catholic University of Louvain Georges Lemaître Centre for Earth and Climate Research(ELI)1348 Louvain-la-NeuveBelgium GNSS Research Center Wuhan UniversityWuhan 430079China State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhan 430079China

In this study,we estimate the absolute vertical land motions at three tidal stations with collocated Global Navigation Satellite System(GNSS)receivers over French Polynesia during the period 2007-2020,and obtain,as ancillary results,estimates of the absolute changes in sea level at the same *** verify our processing approach to determining vertical motion,we first modeled vertical motion at the International GNSS Service(IGS)THTI station located in the capital island of Tahiti and compared our estimate with previous independent determinations,with a good *** obtained the following estimates for the vertical land motions at the tide gauges:Tubuai island,Austral Archipelago-0.92±0.17 mm/yr,Vairao village,Tahiti Iti:-0.49±0.39 mm/yr,Rikitea,Gambier Archipelago-0.43±0.17 mm/*** absolute variations of the sea level are:Tubuai island,Austral Archipelago 5.25±0.60 mm/yr,Vairao village,Tahiti Iti:3.62±0.52 mm/yr,Rikitea,Gambier Archipelago 1.52±0.23 mm/*** discuss these absolute values in light of the values obtained from altimetric measurements and other means in French Polynesia.

关键词： GPS Tide gauges Sea level changes Vertical land motion

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Prediction of net energy of feeds for broiler chickens

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Animal Nutrition 2024年第1期16卷 241-250页

作者： Aye-Cho Tay-Zar Manoosak Wongphatcharachai Pairat Srichana pierre-André Geraert jean Noblet Charoen Pokphand Foods Public Company Limited(CPF) BangkokThailand Adisseo France S.A.S. AntonyFrance INRAE RennesFrance

Net energy(NE)enables the prediction of more accurate feed energy values by taking into account the heat increment which is approximately 25%of apparent metabolizable energy(AME)in ***,application of NE in poultry industry has not been practiced *** predict the NE values of broiler diets,23 diets were prepared by using 13 major ingredients(wheat,corn,paddy rice,broken rice,cassava pellets,full-fat soybean,soybean meal,canola meal,animal protein,rice bran,wheat bran,palm kernel meal and palm kernel oil).The diets were formulated in order to meet the birds'requirements and get a wide range of chemical compositions(on DM basis;33.6%to 55.3%for starch;20.8%to 28.4%for CP,2.7%to 10.6%for ether extract[EE]and 7.0%to 17.2%for NDF),with low correlations between these nutrients and low correlations between the inclusion levels of ingredients allowing for the calculation of robust prediction equations of energy values of diets or *** diets were fed to Ross 308 broilers raised in 12 open-circuit respiratory chambers from 18 to 23 d of age(4 birds per cage)and growth performance,diet AME content and heat production were measured,and dietary NE values were *** trial was conducted on a weekly basis with 12 diets measured each week(1per chamber),1 of the 23 diets(reference diet)being measured each *** diet was tested at least *** total,235 energy balance data values were available for the final *** performance,AME(15.3 MJ/kg DM on average)and AME/GE(79.4%on average)values were as *** NE/AME value averaged 76.6%and was negatively influenced by CP and NDF and positively by EE in connection with efficiencies of AME provided by CP,EE and starch for NE of 73%,87%and 81%,*** best prediction equation was:NE=(0.815×AME)—(0.026×CP)+(0.020×EE)—(0.024×NDF)with NE and AME as MJ/kg DM,and CP,EE and NDF as%of *** NE prediction equations from this study agree with other recently reported equation

关键词： Net energy Broiler Poultry Feed evaluation Energy system

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It’s not all in your feet: Improving penalty kick performance with humanavatar interaction and machine learning

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The Innovation 2024年第2期5卷 115-121页

作者： jean-Luc Bloechle Julien Audiffren Thibaut Le Naour Andrea Alli Dylan Simoni Gabriel Wüthrich jean-pierre Bresciani Control and Perception Laboratory University of FribourgBd Perolles 901700 FribourgSwitzerland Motion-up Le PrismePlace Albert Einstein56000 VannesFrance FC Basel 1893 Birsstrasse 320A4002 BaselSwitzerland

Penalty kicks are increasingly decisive in major international football ***,over 30%of shootout kicks are *** outcome of the kick often relies on the ability of the penalty taker to exploit anticipatory movements of the goalkeeper to redirect the kick toward the open side of the ***,this ability is difficult to train using classical *** used an augmented reality simulator displaying an holographic goalkeeper to test and train penalty kick performance with 13 young elite *** learning algorithms were used to optimize the learning rate by maintaining an optimal level of training *** training sessions of 20 kicks reduced the redirection threshold by 120 ms,which constituted a 28%reduction with respect to the baseline ***,redirection threshold reduction was observed for all trained players,and all things being equal,it corresponded to an estimated 35%improvement of the success rate.

关键词： kick penalty learning

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Liver surface depressions in the presence of diaphragmatic muscular bands on trans-illumination

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World Journal of Experimental Medicine 2024年第2期14卷 5-10页

作者： Shamir O Cawich Michael T Gardner Ramanand Shetty jean pierre Louboutin Zenica Dabichan Shaneeta Johnson Department of Surgery University of the West IndiesSt AugustineTrinidad and Tobago Section of Anatomy Department of Basic Medical SciencesUniversity of the West IndiesKingston KIN7Jamaica Department of Surgery Morehouse School of MedicineAtlantaGA 30310United States

Traditional descriptions of liver anatomy refer to a smooth,convex surface contacting the *** depressions are recognized anatomic *** are many theories to explain the cause of the *** discuss the theory that these are... 详细信息

关键词： Liver Anatomy Depressions Fissure Groove Sulcus Variant

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An ethically guided preclinical device for phenotyping H_(2)production in laboratory rodents

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Animal Models and Experimental Medicine 2024年第4期7卷 553-561页

作者： Victor Pascal-Moussellard Emilie Boucher Stéphane Tanguy Philippe Cinquin pierre-Alain Barraud ChloéDavin Cordélia Salomez-Ihl Dalil Hannani François Boucher jean-pierre Alcaraz University Grenoble Alpes CNRSUMR 5525VetAgro SupGrenoble INPTIMCGrenobleFrance

Background:Dihydrogen(H_(2))is produced endogenously by the intestinal microbiota through the fermentation of diet *** the past few years,numer-ous studies have demonstrated the significant therapeutic potential of H_(2)in various pathophysiological contexts,making the characterization of its production in labora-tory species of major preclinical ***:This study proposes an innovative solution to accurately monitor H_(2)pro-duction in free-moving rodents while respecting animal welfare *** devel-oped device consisted of a wire rodent cage placed inside an airtight chamber in which the air quality was maintained,and the H_(2)concentration was continuously *** the airtightness and efficiency of the systems used to control and maintain air quality in the chamber were checked,tests were carried out on rats and mice with different metabolic phenotypes,over 12 min to 1-h experiments and repeatedly.H_(2)production rates(HPR)were obtained using an easy calculation algorithm based on a first-order moving ***:HPR in hyperphagic Zucker rats was found to be twice as high as in control Wistar rats,respectively,2.64 and 1.27 nmol.s^(−1)per *** addition,the ingestion of inulin,a dietary fiber,stimulated H_(2)production in *** were 0.46 nmol.s^(−1)for animals under control diet and 1.99 nmol.s^(−1)for animals under inulin ***:The proposed device coupled with our algorithm enables fine analysis of the metabolic phenotype of laboratory rats or mice with regard to their endogenous H_(2)production.

关键词： hydrogen therapy laboratory rodents microbiota molecular hydrogen noninvasive monitoring device

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