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Typology and Agroecology of Agroecosystems in Vegetation Dynamics in the Ecotones of the Mbam and Inoubou

Open Journal of Forestry 2024年第1期14卷 42-66页

作者： Alex Bruno Dong Etchike Lucie Félicité Temgoua Bertine Tiokeng Marie Caroline Momo Solefack Martin Benoit Ngassoum Pierre Marie Mapongmetsem Laboratory of Applied Botany Faculty of Sciences of the University of Dschang Dschang Cameroon Department of Forestry Faculty of Agronomy and Agricultural Sciences University of Dschang Dschang Cameroon National School of Agro-Industrial Sciences of the university of ngaoundéré Ngaoundéré Cameroon Laboratory of Biodiversity and Sustainable Development of the university of ngaoundéré Ngaoundéré Cameroon

Agroforestry systems strongly characterize the Cameroonian agrarian landscape. Agroforests are among those structuring the ecotones of Mbam and Inoubou in the Central Cameroon region. Numerous works on agroecosystems of Central and South Cameroon, few have come out contribution of the structure of these traditional systems in the dynamics of the vegetation of these forest-savannah ecotones. The present contribution has the overall objective of demonstrating the structural efficiency of agroforests the dynamics of ecotone vegetation, but also in the conservation of biodiversity. To do this, a participatory analysis was carried out with 56 farmers distributed in the five villages of Makénéné. Botanical inventories supplemented socio-economic household surveys. The data collected was subjected to various analyzes (univariate test, analysis of variance, multivariate test, PCA, CAH). The results reveal that 55.2% of agroforests are less than 15 years old and those with an area greater than 1500 m2 predominate (33%). They are mainly young with generally small surface areas. The horizontal structure reveals that the largest diameter classes are those of [20 - 30 cm[ and [10 - 20 cm[ with a very low rate of basal area. Agroforests with trees over 10 m high are dominant in five villages of Makénéné. Two types of structural profiles characterize the agroforestry flora of the area, namely intensive pluristratified home gardens on savannah and intensive pluristratified agroforests under forest-savannah transition vegetation. Principal Component Analysis (PCA) and Ascending Hierarchical Clustering (HAC) show three Agroforest Clusters each. The PCA distribution reveals that woody biomass (Y) is strongly correlated with tree diameter (DBH) and significantly with height (Cluster 2). The age (AAG) (Cluster 1) of these agroforests, on the other hand, remains independent of the density (DST) of these trees (Cluster 3). The agroforests in the Nyokon, Carrière and Mocksud vil

关键词： Agroforests Agroecosystem Center Cameroon Dynamics Agroecology Typology

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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 Ismaïla 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

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A Budd-Chiari Syndrome Due to C Protein Deficiency: A Case report at YaoundéGeneral Hospital (Cameroon)

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Open Journal of Gastroenterology 2024年第4期14卷 117-124页

作者： Antonin Wilson Ndjitoyap Ndam Gilles Gael Aghoagni Gouajio Armel Awana Tenone Danah Larry Tangie Ngek Mathurin Kowo Firmin Andoulo Ankouane Elie Claude Ndjitoyap Ndam Department of Internal Medicine Faculty of Medicine and Biomedical Sciences University of Yaoundé 1 Yaoundé Came-roon Department of Internal Medicine and Peadiatrics Faculty of Health Sciences University of Buéa Buéa Cameroon Department of Biomedical Sciences Faculty of Sciences University of Ngaoundéré Ngaoundéré Cameroon

Primary Budd-Chiari syndrome (BCS) is a spontaneously fatal disease characterized by an obstruction of the hepatic venous outflow tract due to thrombosis or a primary disease of the venous wall. The primary form of BCS is extremely rare. This is a disease mainly affecting young adults of both sexes. Clinical manifestations are variable;they can be asymptomatic, acute, or subacute but mostly chronic. Several causes have been identified, such as myeloproliferative syndrome, antiphospholipid syndrome, paroxysmal nocturnal hemoglobinuria, and inherited thrombotic disorders. Data on primary BCS in Sub-Saharan Africa is rare as most publications available are case reports. In these reports, the causes are unknown with poor prognosis in most cases often leading to patient death. We herein present a case report of a male patient diagnosed with a primary BCS at Yaoundé General Hospital (Cameroon) caused by a Protein C deficiency who presented with ascites decompensating liver cirrhosis. Treatment was based on anticoagulants, diuretics and laxatives administration. Two years after the diagnosis, the patient is alive with clinical and paraclinical improvement.

关键词： Budd-Chiari Syndrome Hepatic Veins Liver Cirrhosis Protein C Deficiency Cameroon

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Semisynthetic Derivatives of Sissotrin Isolated from Trifolium baccarinii Chiov. (Fabaceae) and Evaluation of Their Antibacterial Activities

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Advances in Biological Chemistry 2024年第1期14卷 27-39页

作者： Donald Léonel Feugap Tsamo Cyrille Ngoufack Tagousop Arnaud Joseph Nguetse Dongmo Laurence Voutquenne-Nazabadioko David Ngnokam research Unit of Applied and Environmental Chemistry Department of Chemistry Faculty of Science University of Dschang Dschang Cameroon Department of Organic Chemistry Faculty of Science University of Yaoundé I Yaoundé Cameroon Department of Basic Scientific Studies University Institute of Technology University of Ngaoundéré Ngaoundéré Cameroon Groupe Isolement et Structure Institut de Chimie Moléculaire de Reims (ICMR) Reims France

Starting from sissotrin (1), a natural isoflavonoid isolated from Trifolium baccarinii (Fabaceae), one new semisynthetic derivative, 6-nitrobiochanin A (1b) and two known derivatives, 8-nitrobiochanin A (1a) and 2",3",4",6"-tetraacetylsissotrin (1c) have been obtained after performing nitration and acetylation reactions. Their structures were assigned after interpretation of their spectrometric (Hr-ESI-MS) and spectroscopic (NMr 1D and 2D) data and by comparison with those reported in the literature. The substrate as well as the semisynthetic derivatives were evaluated for their antibacterial activities against six strains. The results reveal that they are inactive or weakly active on the strains tested with the exception of 8-nitrobiochanin A (1a) which showed moderate activity (MIC = 62.5 μg∙mL−1) on Staphylococcus aureus ATCC 43300.

关键词： Trifolium baccarinii Isoflavonoid Nitration Acetylation Antibacterial Activity

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Celebrating the 20th Anniversary of the Department of Chemistry at renmin university of China

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Chemical research in Chinese Universities 2024年第5期40卷 761-763页

作者： WANG Yapei School of Chemistry and Life resources Renmin University of ChinaBeijing 100872P.R.China

Established in 2004,the Department of Chemistry was the first entity of the School of Science at renmin university of China,marking the inception of a new era in the university's pursuit of scientific *** embarked on its academic mission by admitting its first batch of undergraduate and master's students in the same year,and by 2008,it had leaped forward by enrolling its first doctoral candidates.A decade after its establishment,in 2015,the department began to enter the top 1%of global chemistry disciplines in the ESI rankings,a first for renmin university of *** 2022,the major of chemistry was awarded as the national first-class undergraduate major construction site.

关键词： batch pursuit undergraduate

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Floristic Diversity and Conservation Status of Guineo-Congolese Species in Southeastern Cameroon: The Case of the Gari-Gombo Communal Forest

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Open Journal of Forestry 2024年第1期14卷 87-97页

作者： Boris Nyeck Valery Noiha Noumi Nicole Maffo Maffo Victor Awe Djongmo Cedric Djomo Chimi Louis Zapfack Department of Biological Sciences Faculty of Sciences University of Ngaoundéré Ngaoundéré Cameroon Agricultural research Institute for Development (IrAD) Minko Agricultural Research Station Meyomessala Cameroon Department of live Sciences Higher Teacher Training College University of Bertoua Bertoua Cameroon Department of Plant Biology and Physiology Faculty of Sciences University of Yaoundé I Yaoundé Cameroon Agricultural research Institute for Development (IrAD) Research Station of Yokadouma Yokadouma Cameroon

The conservation of plant biodiversity has become one of the most important objectives in the sustainable management of Guinean-Congolese ecosystems. However, in the south-east zone of Cameroon, there is a lack of rigor in the management of these forests, which can result in the loss of species of high conservation value. The study was carried out in communal forests in the south-east zone of Cameroon. Its aim was to carry out a floristic inventory and then compare the list of species with the IUCN catalog. Twenty-four plots, each with a surface area of 0.2 ha, were set up in the Gari-Gombo communal forest. All timbers with a DBH ≥ 5 cm were systematically counted. A total of 176 species, belonging to 144 genera and 45 families, were surveyed. Fabaceae (42.08%), Malvaceae (39%), Euphorbiaceae (24.64%), Moraceae (20.92%), Apocynaceae (18.64%), Cecropiaceae (16.60%), Ulmaceae (14.76%), Meliaceae (14.61%), Violaceae (14.08%), Combretaceae (12.67%), Theobroma cacao (21.17%), Baphia leptobotrys (18.06%), rinorea sp. (14.09%), Musanga cecropioides (12.18%), Terminalia superba (10.32%), Neosloetiopsis kamerunensis (10.14%), Celtis zenkeri (8.29%) and Alstonia boonei (7.77%) were the most important taxa. Nearly 90% of the species in this forest are Guinean species, with a dominance of Guinean-Congolese species (66%). Fourteen (14) threatened species have been identified in the FCGG. This study, which highlights the rich biodiversity of communal forests, is important for guiding biodiversity conservation policies in ecosystems used for production.

关键词： Communal Forest Conservation Status Cameroon Floristic Diversity

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Nuclearity and Finite-representability in the System of Completely Integral Mapping Spaces

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1197-1214页

作者： Zhe DONG Ji Cheng TAO Ya Fei ZHAO Department of Mathematics Zhejiang UniversityHangzhou 310027P.R.China Department of Mathematics China Jiliang UniversityHangzhou 310018P.R.China Department of Mathematics Zhejiang International Studies UniversityHangzhou 310023P.R.China

In this paper,we investigate local properties in the system of completely integral mapping *** introduce notions of injectivity,local reflexivity,exactness,nuclearity,finite-represent ability and WEP in the system of completely integral mapping *** we obtain that any finite-dimensional operator space is injective in the system of completely integral mapping *** we prove that C is the unique nuclear operator space and the unique exact operator space in this *** also show that C is the unique operator space which is finitely representable in{T_(n)}n∈Nin this *** corollaries,Kirchberg’s conjecture and QWEP conjecture in the system of completely integral mapping spaces are false.

关键词： Completely integral mapping space injectivity exactness nuclearity finite-representability WEP

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The Extension Dimension of Subcategories and recollements of Abelian Categories

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Acta Mathematica Sinica,English Series 2024年第4期40卷 1042-1058页

作者： Xin MA Ye Yang PENG Zhao Yong HUANG College of Science Henan University of EngineeringZhengzhou 451191P.R.China Department of Mathematics Nanjing UniversityNanjing 210093P.R.China

We investigate the behavior of the extension dimension of subcategories of abelian categories under ***Λ',Λ,Λ"be art in algebras such that(modΛ',mod A,modΛ")is a recollement,and let D'and D"be subcategories of modΛand modΛ"*** any n,m≥0,under some conditions,we get dimΩ^(k)(D)≤dimΩ^(n)(D')+dimΩ^(m)(D")+1,where k=max{m,n}and D is the subcategory of modΛglued by D'and D";moreover,we give a sufficient condition such that the converse inequality holds *** applications,some results for Igusa-Todorov subcategories and syzygy finite sub categories are obtained.

关键词： recollements extension dimension Igusa–Todorov subcategories syzygy finite subcategories

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reducing Subspaces of Toeplitz Operators Induced by a Class of Non-analytic Monomials over the Unit Ball

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Acta Mathematica Sinica,English Series 2024年第7期40卷 1767-1777页

作者： Yan Yue SHI Bo ZHANG Xu TANG Yu Feng LU School of Mathematical Sciences Ocean University of ChinaQingdao 266100P.R.China School of Mathematics and Information Sciences Yantai UniversityYantai 264005P.R.China School of Mathematical Sciences Space Engineering UniversityBeijing 101416P.R.China School of Mathematical Sciences Dalian University of TechnologyDalian 116024P.R.China

In this paper,we describe the minimal reducing subspaces of Toeplitz operators induced by non-analytic monomials on the weighted Bergman spaces and Dirichlet spaces over the unit ball B_(2).It is proved that each minimal reducing subspace M is finite dimensional,and if dim M≥3,then M is induced by a ***,the structure of commutant algebra v(T_(w)N_(z)N):={M^(*)_(w)NM_(z)N,M^(*)_(z)NM_(w)N}′is determined by N and the two dimensional minimal reducing subspaces of(T_(w)N_(z)*** also give some interesting examples.

关键词： reducing subspace operator-weighted shifts Toeplitz operator von Neumann algebra

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Homological Transfer between Additive Categories and Higher Differential Additive Categories

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1325-1344页

作者： Xi TANG Zhao Yong HUANG School of Science Guilin University of Aerospace TechnologyGuilin 541004P.R.China Department of Mathematics Nanjing UniversityNanjing 210093P.R.China

Given an additive category C and an integer n≥*** higher differential additive category consists of objects X in C equipped with an endomorphism ϵ_(X)satisfying ϵ_(X)^(n).Let r be a,finite-dimensional basic algebra over an algebraically closed field and T the augmenting functor from the category of finitely generated left r-modules to that of finitely generated left r/(t^(n))-*** is proved that a finitely generated left r-module M isτ-rigid(respectively,(support)τ-tilting,almost completeτ-tilting)if and only if so is T(M)as a left r[t]/(t^(n))-***,r isτm-selfinjective if and only if so is r[t]/(t^(n)).

关键词： Higher differential objects Wakamatsu tilting subcategories G_(ω)-projective modules sup-portτ-tilting modules τ_(m)-selfinjective algebras precluster tilting subcategories

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