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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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Petrographic and geochemical characterization of weathered materials developed on BIF from the Mamelles iron ore deposit in the Nyong unit, South-West Cameroon

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Acta Geochimica 2021年第2期40卷 163-175页

作者： Tessontsap Teutsong jean pierre temga Armelle Ayissi Enyegue Nicodeme Noel Feuwo Dieudonne Bitom Department of Earth Sciences University of Yaounde IP.O.Box 812YaoundeCameroon Ministry of Mines Industry and Technological DevelopmentYaoundeCameroon University of Dschang P.O.Box 96Dschang.Cameroon

Iron ore deposits hosted by Precambrian banded iron formation(BIF)are the most important source of mineable *** Cameroon,they are located in the southern part of the *** study reports the petrological and geochemical data of iron ores collected from a weathering profile in the Mamelles BIF deposit,SW *** profile is composed of three levels which are from the bottom to the top:the saprock,the ferruginous horizon,and the loose *** representative iron ore samples(rock fragments and loose clayey material)were collected along the profile and were subjected to petrographic and geochemical *** mineralogy consists of martite,goethite,quartz,and lesser amounts of hematite,magnetite,kaolinite,and *** presence of minerals such as kaolinite and goethite in the Mamelles iron ores suggests their supergene ***,the saprock is characterized by high iron content(70.25 wt%Fe_(2)O_(3) t),and low silica(26.38 wt%SiO_(2))and alumina(1.14 wt%Al_(2) O_(3)).The rock fragments collected from the ferruginous horizon display higher Fe2 O3 t(72-76.40 wt%),Al_(2) O_(3)(2.80-5.43 wt%),and lower SiO_(2)(16.70-18.35 wt%)contents,suggesting the leaching of silica during the enrichment *** loose clayey samples collected from both the ferruginous horizon and the upper loose horizon show lower iron and higher silica *** normalized to the underlying BIF saprock,both rock fragments and loose clayey ores display LREE enrichment,suggesting that they formed through supergene ***,most of the Mamelles iron ores are classified as medium-grade ores and a few display acceptable contents in ***,this petrological and geochemical study of the Mamelles iron ores revealed encouraging *** its strategic location near the deep seaport,the deposit should be investigated in more detail for its mining potential.

关键词： Mamelles BIF Medium-grade iron ore Supergene origin Nyong unit Cameroon

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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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Re-evaluation of recent research on metabolic utilization of energy in poultry: Recommendations for a net energy system for broilers

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Animal Nutrition 2024年第1期16卷 62-72页

作者： jean Noblet Aye-Cho Tay-Zar Shu-Biao Wu Pairat Srichana pierre Cozannet pierre-Andre Geraert Mingan Choct INRAE Charoen Pokphand Foods Public Company Limited (CPF) School of Environmental and Rural Science University of New England Adisseo France S.A.S.

Different energy systems have been proposed for energy evaluation of feeds for domestic animals. The oldest and most commonly used systems take into account the fecal energy loss to obtain digestible energy(DE), and fecal, urinary and fermentation gases energy losses to calculate metabolizable energy(ME). In the case of ruminants and pigs, the net energy(NE) system, which takes into account the heat increment associated with the metabolic utilization of ME, has progressively replaced the DE and ME systems over the last 50 years. For poultry, apparent ME(AME) is used exclusively and NE is not yet used widely. The present paper considers some important methodological points for measuring NE in poultry feeds and summarizes the available knowledge on NE systems for poultry. NE prediction equations based on a common analysis of three recent studies representing a total of 50 complete and balanced diets fed to broilers are proposed; these equations including the AME content and easily available chemical indicators have been validated on another set of 30 diets. The equations are applicable to both ingredients and complete diets. They rely primarily on an accurate and reliable AME value which then represents the first limiting predictor of NE value. Our analysis indicates that NE would be a better predictor of broiler performance than AME and that the hierarchy between feeds is dependent on the energy system with a higher energy value for fat and a lower energy value for protein in an NE system. Practical considerations for implementing such an NE system from the commonly used AME or AMEn(AME adjusted for zero nitrogen balance) systems are presented. In conclusion, there is sufficient information to allow the implementation of the NE concept in order to improve the accuracy of feed formulation in poultry.

关键词： Poultry Feed evaluation Net energy Energy system

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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) Adisseo France S.A.S. INRAE

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 widely. To 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 ingredients. These 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 calculated. The 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 week. Each diet was tested at least 8times. In total, 235 energy balance data values were available for the final calculations. Growth performance, AME(15.3 MJ/kg DM on average) and AME/GE(79.4% on average) values were as expected. The 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%,respectively. The 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 DM. The NE prediction

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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Application of novel constrained friction processing method to produce fine grained biomedical Mg-Zn-Ca alloy

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Journal of Magnesium and Alloys 2024年第2期12卷 516-529页

作者： Ting Chen Banglong Fu Junjun Shen Uceu F.H.R.Suhuddin Björn Wiese Yuanding Huang Min Wang Jorge F.dos Santos jean pierre Bergmann Benjamin Klusemann Solid State Materials Processing Institute of Material MechanicsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Functional Magnesium Materials Institute of Metallic BiomaterialsHelmholtz-Zentrum HereonMax-Planck-Str.1Geesthacht 21502Germany Shanghai Key Laboratory of Materials Laser Processing and Modification Shanghai Jiao Tong UniversityDongchuan Road 800Shanghai 200240China Applied Materials and Manufacturing Energy and Environment DivisionPacific Northwest National LaboratoryPO Box 999RichlandWA 99352USA Production Technology Group Technisiche Universität IlmenauGustav-Kirchhoff-Platz 2Ilmenau 98693Germany Institute for Production Technology and Systems Leuphana University of LüneburgUniversitätsallee 1Lüneburg 21335Germany

In order to obtain Mg alloys with fine microstructures and high mechanical performances,a novel friction-based processing method,name as“constrained friction processing(CFP)”,was *** CFP,defect-free Mg-Zn-Ca rods with greatly refined grains and high mechanical properties were *** to the previous as-cast microstructure,the grain size was reduced from more than 1 mm to around 4μm within 3 s by a single process *** compressive yield strength was increased by 350%while the ultimate compressive strength by 53%.According to the established material flow behaviors by“tracer material”,the plastic material was transported by shear *** the base material to the rod,the material experienced three stages,*** by the tool,upward flow with additional tilt,followed by upward *** microstructural evolution was revealed by“stop-action”*** microstructural development at regions adjacent to the rod is mainly controlled by twinning,dynamic recrystallization(DRX)as well as particle stimulated nucleation,while that within the rod is related to DRX combined with grain growth.

关键词： Constrained friction processing Magnesium alloys Microstructure Mechanical properties Grain refinement Plastic deformation

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