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Petrology of Spinel-lherzolite Xenoliths from Mazéléand Others Northen Xenoliths localities of Cameroon Volcanic line: Exchange Reactions and Equilibrium State

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Open Journal of Geology 2024年第5期14卷 629-653页

作者： Nguihdama Dagwai Kamgang Pierre Mbowou Gbambié Isaac Bertrand Chazot Gilles Ngounouno isma.la Department of life and Earth Sciences Higher Teachers&#8217 Training College University of Maroua Maroua Cameroon Department of Earth Sciences Faculty of Science University of Yaound&#233 1 Yaound&#233 Cameroon Department of Mineral Prospecting and Exploration Technologies School of Geology and Mining Engineering University of Ngaoundere Meiganga Cameroon Ocean Geosciences laboratory European University Institute of the Sea (IUEM) Brest France

The alkaline volcanism of the Cameroon Volcanic line in its northern domain has raised many fresh enclaves of peridotites. The samples selected come from five (05) different localities (liri, in the plateau of Kapsiki, Mazélé in the NE of Ngaoundéré, Tello and Ganguiré in the SE of Ngaoundéré and likok, locality located in the west of Ngaoundé). The peridotite enclaves of the above localities show restricted mineralogical variation. Most are four-phase spinel-lherzolites, indicating that this is the main lithology that forms the lithospheric mantle below the shallow zone. No traces of garnet or primary plagioclase were detected, which strongly limits the depth range from which the rock fragments were sampled. The textures and the wide equilibrium temperatures (884˚C - 1115˚C) indicate also entrainment of lherzolite xenoliths from shallow depths within the lithosphere and the presence of mantle diapirism. The exchange reactions and equilibrium state established in this work make it possible to characterize the chemical composition of the upper mantle of each region and test the equilibrium state of the phases between them. Variations of major oxides and incompatible elemental concentrations in clinopyroxene indicate a primary control by partial melting. The absence of typical “metasomatic” minerals, low equilibration temperatures and enriched lREE patterns indicate that the upper mantle below septentrional crust of Cameroun underwent an event of cryptic metasomatic enrichment prior to partial melting. The distinctive chemical features, lREE enrichment, strong U, Ce and Pr, depletion relative to Ba, Nb, la, Pb, and T, fractionation of Zr and Hf and therefore ligh high Zr/Hf ratio, low la/Yb, Nb/la and Ti/Eu are all results of interaction of refractory peridotite residues with carbonatite melts.

关键词： Xenoliths Upper Mantle Northern Region Adamawa Cameroon Volcanic line Exchange Reaction

Gastrointestinal Ulcers Treatment: Plants and Recipes Used by Herbalists of Abomey-Calavi and Cotonou Districts, Southern Benin

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American Journal of Plant Sciences 2024年第9期15卷 699-725页

作者： Brice Dangnon Durand Dah-Nouvlessounon Sêmassa Mohamed isma.l Hoteyi Abdelmalick Abdelrahman Moubachar Abdelkerim Mahamat Nicodème Worou Chabi Sina Haziz Farid Baba-Moussa Adolphe Adjanohoun lamine Baba-Moussa laboratory of Biology and Molecular Typing in Microbiology Department of Biochemistry and Cell Biology Faculty of Science and Technology University of Abomey-Calavi Cotonou Benin Unit of Biochemistry and Molecular Markers in Nutrition Laboratory of Research in Applied Biology Polytechnic School of Abomey-Calavi University of Abomey-Calavi Cotonou Benin laboratoire de Microbiologie et de Technologie Alimentaire Faculty of Science and Technology University of Abomey-Calavi Cotonou Benin Institut National des Recherches Agricoles du Bnin Cotonou Benin

This study set out to identify plants and recipes used by herbalists in the municipalities of Abomey-Calavi and Cotonou to treat gastrointestinal ulcers and to characterize the distribution of their knowledge. An ethno-pharmacological survey was carried out in which informants who agreed freely were interviewed using a semi-structured questionnaire. A total of 85 herbalists were surveyed. The data were processed with Microsoft Excel to calculate the relative frequencies of citation of the various species mentioned by the herbalists and various indices including Simpson’s Index were adapted to test the distribution of their knowledge. Multiple regression and correspondence analysis were performed using R studio. Our results revealed that the Dendi, Ifè and Mina, all equitable in their knowledge of anti-ulcer plants, are likely to know more than the other ethnic groups. On the other hand, respondents practicing Islam are more likely to know many antiulcer plants than those practicing Vodoun and Christianity. This constant distribution of knowledge of anti-ulcer plants among the Dendi, Ifè and Mina, three different ethnic groups seems normal and attests to the fusion between these different ethnic groups in view of this knowledge. A total of 70 anti-ulcer recipes, made from 71 species of medicinal plants or non-floristic resources were recorded. Vitellaria paradoxa, Parkia biglobosa and Ocimum gratissimum were the top 03 most frequently cited in descending order of frequency. All the species cited are grouped into 44 botanical families among which the Fabaceae, lamiaceae and Sapotaceae were strongly represented. Benin’s flora abounds in a diversity of medicinal plant species known to herbalists in Abomey-Calavi and Cotonou for the treatment of gastrointestinal ulcers. The results of this study constitute a good archive for the selection of plant species for in-depth studies with a view to formulating improved traditional medicines for gastrointestinal ulcers.

关键词： Gastrointestinal Ulcer Ethnomedicine Herbalist Nature Plant Material

Structural Controls and Predictive Mapping of Tin, Niobium and Tantalum Mineralization Associated with the Mayo Darlé Stanniferous Granitoids;Contributions of Geostatistics

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Journal of Geoscience and Environment Protection 2024年第1期12卷 180-210页

作者： Bah-Yero liman Ngounouno isma.la Mbowou Gbambié Isaac Bertrand Alpha Baster Kenfack Fokem André William Boroh Amadou Diguim Kepnamou Department of Earth Sciences Faculty of Science University of Ngaoundéré Ngaoundéré Cameroon Department of Mining Geology School of Geology and Mining and Engineering University of Ngaoundéré Meiganga Cameroon Department of Earth Sciences Faculty of Science University of Garoua Garoua Cameroon

The aim of this study of the spatial dispersion of tin, niobium and tantalum mineralization associated with the Mayo Darlé granitoids was to produce prospecting guides through predictive maps of Sn, Nb and Ta in the region. It was based on a database (in appendix) obtained after analysis of rock samples (greisens and quartz veins) collected in the field, using a portable X-ray fluorescence (XRF) spectrometer. Two approaches were used: 1) structural studies in the field using the directions of veins and fractures 2) the use of variographic maps, an essential element in geostatistics for determining directional anisotropies. A joint synthesis of the modelling results shows that tin, tantalum and niobium mineralization at Mayo Darlé is concentrated along strike intervals N315E to N320E, with mineralization also occurring along strike N35E for high-grade Sn, medium-grade Ta and low-grade Nb. In short, mineral concentrations disperse progressively in space: positively from east to west for tantalum and niobium, and inversely for tin.

关键词： Mayo Darlé Tin Niobium Tantalum Geostatistics Mapping

On the functions of astrocyte-mediated neuronal slow inward currents

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Neural Regeneration Research 2024年第12期19卷 2602-2612页

作者： Balázs Pál Department of Physiology Faculty of MedicineUniversity of DebrecenDebrecenHungary

Slow inward currents are known as neuronal excitatory currents mediated by glutamate release and activation of neuronal extra synaptic N-met hyl-D-aspartate receptors with the contribution of *** events are significantly slower than the excitatory postsynaptic *** of slow inward currents are determined by seve ral factors including the mechanisms of astrocytic activation and glutamate release,as well as the diffusion pathways from the release site towards the extra synaptic recepto *** are stimulated by neuronal network activity,which in turn excite neurons,forming an astrocyte-neuron feedback *** as a consequence of brain edema,astrocytic swelling can also induce slow inward currents under pathological *** is a growing body of evidence on the roles of slow inward currents on a single neuron or local network *** events often occur in synchro ny on neurons located in the same astrocytic *** synchronization of neuronal excitability,slow inward currents also set synaptic strength via eliciting timing-dependent synaptic *** addition,slow inward currents are also subject to non-synaptic plasticity triggered by long-la sting stimulation of the excitatory *** note,there might be important regionspecific differences in the roles and actions triggering slow inward *** greater networks,the pathophysiological roles of slow inward currents can be better understood than physiological *** inward currents are identified in the pathophysiological background of autism,as slow inward currents drive early hypersynchrony of the neural *** inward currents are significant contributors to paroxysmal depolarizational shifts/interictal *** events are related to epilepsy,but also found in Alzheimer's disease,Parkinson's disease,and stroke,leading to the decline of cognitive *** with features overlapping with slow inward currents(excitatory,N-methyl-Dasp

关键词： astrocyte cortical spreading depolarization gliotransmission glutamate neural synchronization NMDA receptor paroxysmal depolarizational shift slow inward current

On calculating glacial isostatic adjustment

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Geodesy and Geodynamics 2024年第5期15卷 441-452页

作者： l.M.Cathles Cornell University IthacaNY 14853USA

Modeling the earth's fluid and elastic response to the melting of the glaciers of the last ice age is the most direct way to infer the earth's radial viscosity ***,we compare two methods for calculating the viscoelastic response to surface *** one,the elastic equation of motion is converted to a viscoelastic equation using the Correspondence *** the other,elastic deformation is added to the viscous flow as isostatic adjustment *** two modeling methods predict adjustment histories that are different enough to potentially impact the interpretation of the observed glacial isostatic adjustment(GIA).The differences arise from buoyancy and whether fluid displacements are subjected to hydrostatic *** methods agree if they use the same equations and boundary *** origin of the differences is determined by varying the boundary conditions and pre-stress application.

关键词： Glacial isostatic adjustment Viscoelastic normal modes Hydrostatic pre-stress Elastic buoyancy Correspondence principle

Effect of radiative loss mechanisms on FIR thermometric parameters of Nd^(3+)-doped lithium tellurite glasses

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Journal of Rare Earths 2024年第7期42卷 1250-1257,I0002页

作者： C.Y.Morassuti A.P.l Silva l.A.O.Nunes S.M.lima l.H.C.Andrade Optical and Photothermal Spectroscopy Group(GEOF) Center for Studies in Natural Resources(CERNA)State University of Mato Grosso do Sul(UEMS)C.P.351DouradosMSBrazil Renato Archer Information Technology Center Dom Pedro I Highway(SP-65)Km 1436-Chácaras Campos dos AmaraisCampinasSPBrazil Institute of Physics of São Carlos University of São PauloSão CarlosSPBrazil

Nd^(3+)-doped tellurite glasses are promising materials for thermometers based on the fluorescence intensity ratio(FIR)***,at high Nd^(3+)concentrations,energy transfer(ET)processes such as optical reabsorption and cross-relaxation can affect the Nd^(3+)emission,which has been little explored in the ***,the present work investigated the use of Nd^(3+)-doped tellurite glass(samples doped with Nd^(3+)at 0.2 mol%,0.5 mol%,2.0 mol%,and 4.0 mol%)in fluorescence thermometers,in the temperature range from 299 to 371 *** results indicate a strong dependence of the FIR parameters on the Nd^(3+)concentration,due to changes in the emission band profiles caused by optical reabsorption of the Nd^(3+)emissions and cross-relaxation processes.A decrease of the relative sensitivity of the ratio^(4)F_(5/2)→^(4)I_(9/2)/^(4)F_(3/2)→^(4)I_(9/2)is observed for samples doped with higher amounts of Nd^(3+).The maximum relative sensitivity at 299 K is 3.00%/K,which is the highest value among the reported Nd^(3+)ions.

关键词： Nd^(3+)-doped tellurite glass Fluorescence intensity ratio Optical thermometry Judd-Ofelt Rare earths

Non-adhesive and adhesive contacts of an elastic quarter-or eighth-space with freely sliding sides

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Friction 2024年第9期12卷 2052-2063页

作者： Qiang lI Valentin l.POPOV Technische Universität Berlin Berlin 10623Germany

The contact of an elastic quarter-or eighth-space is studied under the condition that the movement of the side surface of the quarter-space is constrained:It can slide freely along the plane of the side surface but its normal movement is blocked(for example,by a rigid wall).The solution of this contact problem can be easily achieved by additionally applying a mirrored load to an elastic ***-adhesive contact and the Johnson–Kendall–Roberts(JKR)-type adhesive contact between a rigid sphere and an elastic quarter-space under such a boundary condition is numerically simulated using the fast Fourier transform(FFT)-assisted boundary element method(BEM).Contacts of an elastic eighth-space are investigated using the same *** on the position of the sphere relative to the side edge,different contact behavior is *** the case of adhesive contact,the force of adhesion first increases with increasing the distance from the edge of the quarter-space,achieves a maximum,and decreases further to the JKR-value in large distance from the *** enhancement of the force of adhesion compared to the half-space-contact is associated with the pinning of the contact area at the *** provide the maps of the force of adhesion and their analytical approximations,as well as pressure distributions in the contact plane and inside the quarter-/eighth-space.

关键词： quarter-space eighth-space adhesion edge effect boundary element method(BEM)

Quantum vortices get stretched

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Frontiers of physics 2024年第3期19卷 225-227页

作者： Emanuel A.l.Henn São Carlos Institute of Physics University of São Paulo-PO Box 36913560-970São CarlosBrazil

Since its discovery, superfluidity [1,2] remains one of the most remarkable phenomena in quantum physics. The onset of the quantum regime in liquid helium is visually striking, when the fluid flows without dissipation or detaches from a rotating bucket, remaining still upon soft rotations. The same phenomenon is present in the context of ultracold bosonic quantum gases where, most of the time, superfluidity walks hand-in-hand with the transition to Bose−Einstein condensation [3].

关键词： quantum rotating rotation

Time-inconsistent stochastic linear-quadratic control problem with indefinite control weight costs

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Science China Mathematics 2024年第1期67卷 211-236页

作者： Qi lü Bowen Ma School of Mathematics Sichuan UniversityChengdu 610064China

A time-inconsistent linear-quadratic optimal control problem for stochastic differential equations is *** introduce conditions where the control cost weighting matrix is possibly *** such conditions,we obtain a family of closed-loop equilibrium strategies via multi-person differential *** result extends Yong’s work(2017) in the case of stochastic differential equations,where a unique closed-loop equilibrium strategy can be derived under standard conditions(namely,the control cost weighting matrix is uniformly positive definite,and the other weighting coefficients are positive semidefinite).

关键词： linear-quadratic optimal control problem time-inconsistent cost functional generalized Riccati equation indefinite control weight cost closed-loop equilibrium strategy