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Farmers' contributions to the conservation of tree diversity in the Groundnut Basin,Senegal

Journal of Forestry Research 2017年第5期28卷 1083-1096页

作者： Antoine Sambou Bienvenu Sambou Anders R?bild Department of Geosciences and Natural Resource Management Faculty of ScienceUniversity of Copenhagen Institut des Sciences de l'Environnement (ISE) Facultdes Sciences et TechniqueUniversitCheikh Anta Diop(UCAD)

Tree diversity in West Africa is threatened by intensified land uses and salinization, and farmers’ role in conservation of tree species is unclear. We hypothesized that farmers contribute to conservation of tree diversity through protection of trees in their agroforestry landscapes and compared the diversity and structure of the tree vegetation across landscape classes. Inventories were carried out in three villages in the Groundnut Basin in Senegal, assessing tree diversity, density and crown cover. Tree diversity as assessed by species accumulation curves was high in forests, but cultivated landscapes had comparable or almost comparable diversity, especially in the cases where the forest was planted or was affected by charcoal production. However, the occurrence of exotic species was higher in cultivated parts of the landscape, and although many species were in common, ordination plots indicated that forests and cultivated landscapes to some degree had different species composition. Salinity had a strong influence on vegetation, not only in the tans (salt marshes) but also across the other landscape classes. In conclusion, agroforestry landscapes in the three villages harbor considerable tree diversity, but insufficient to fully conserve the tree species. We argue that informing and including farmers in tree management in the region will contribute to overall conservation of tree genetic resources.

关键词： Tree diversity Conservation-landscape classes Environmental factors Groundnut Basin

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Large-Scale Estimation of Distribution Algorithms with Adaptive Heavy Tailed Random Pro jection Ensembles

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Journal of Computer Science & Technology 2019年第6期34卷 1241-1257页

作者： Momodou L.Sanyang Ata Kabán School of Computer Science University of BirminghamEdgbastonBirmingham B152TTU.K. School of Information Technology and Communication University of The GambiaSerekundaThe Gambia

We present new variants of Estimation of Distribution Algorithms (EDA) for large-scale continuous optimisation that extend and enhance a recently proposed random projection (RP) ensemble based approach. The main novelty here is to depart from the theory of RPs that require (sub-)Gaussian random matrices for norm-preservation, and instead for the purposes of high-dimensional search we propose to employ random matrices with independent and identically distributed entries drawn from a t-distribution. We analytically show that the implicitly resulting high-dimensional covariance of the search distribution is enlarged as a result. Moreover, the extent of this enlargement is controlled by a single parameter, the degree of freedom. For this reason, in the context of optimisation, such heavy tailed random matrices turn out to be preferable over the previously employed (sub-)Gaussians. Based on this observation, we then propose novel covariance adaptation schemes that are able to adapt the degree of freedom parameter during the search, and give rise to a flexible approach to balance exploration versus exploitation. We perform a thorough experimental study on high-dimensional benchmark functions, and provide statistical analyses that demonstrate the state-of-the-art performance of our approach when compared with existing alternatives in problems with 1000 search variables.

关键词： covariance adaptation estimation of distribution algorithm random projection ensemble t-distribution

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Livestock induces strong spatial heterogeneity of soil CO2, N2O and CH4 emissions within a semi-arid sylvo-pastoral landscape in West Africa

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Journal of Arid Land 2017年第2期9卷 210-221页

作者： Mohamed H ASSOUMA Dominique SERCA Frederic GUERIN Vincent BLANFORT Philippe LECOMTE Ibra TOURE Alexandre ICKOWICZ Raphael J MANLAY Martial BERNOU Jonathan VAYSSIERES CIRAD-UMR Selmet Campus International Baillarguet Montpellier 34398 France DP PPZS ISRA-LNERV BP 2057 Dakar Hann Senegal Laboratoire d'Aerologie-OMP Universite Paul Sabatier 14 Avenue Edouard Belin Toulouse 31400 France Geosciences Environnement Toulouse UMR 5563 & UR 234 IRD Universite Paul Sabatier Avenue Edouard Belin 14 Toulouse 31400 France CILSS 03 BP 7049 Ouagadougou Burkina Faso AgroParisTech-UMR Eco&Sols 2 place Viala Montpellier SupAgro Montpellier 34060 France IRD-UMR Eco&Sols 2 place Viala Montpellier SupAgro Montpellier 34060 France

Greenhouse gas （GHG） emissions from the surface soils and surface water receiving animal excreta may be important components of the GHG balance of terrestrial ecosystems, but the associated processes are poorly documented in tropical environments, especially in tropical arid and semi-arid areas. A typical sylvo-pastoral landscape in the semi-arid zone of Senegal, West Africa, was investigated in this study. The study area （706 km2 of managed pastoral land） was a circular zone with a radius of 15 km centered on a borehole used to water livestock. The landscape supports a stocking rate ranging from 0.11 to 0.39 tropical livestock units per hectare depending on the seasonal movements of the livestock. Six landscape units were investigated （land in the vicinity of the borehole, natural ponds, natural rangelands, forest plantations, settlements, and enclosed plots）. Carbon dioxide （CO2）, nitrous oxide （N2O） and methane （CH4） fluxes were measured with static chambers set up at 13 sites covering the six landscape units, and the 13 sites are assumed to be representative of the spatial heterogeneity of the emissions. A total of 216 fluxes were measured during the one-year study period （May 2014 to April 2015）. At the landscape level, soils and surface water emitted an average 19.8 t C-CO2 eq/（hm2.a）（CO2： 82%, N2O： 15%, and CH4： 3%）, but detailed results revealed notable spatial heterogeneity of GHG emissions. CO2 fluxes ranged from 1148.2 （±91.6） mg/（m2.d） in rangelands to 97,980.2 （±4,861.7） mg/（m2.d） in surface water in the vicinity of the borehole. N2O fluxes ranged from 0.6 （±0.1） mg/（m2.d） in forest plantations to 22.6 （±10.8） mg/（m2.d） in the vicinity of the borehole. CH4 fluxes ranged from -3.2 （±0.3） mg/（m2.d） in forest plantations to 8788.5 （±2295.9） mg/（m2.d） from surface water in the vicinity of the borehole. This study identified GHG emission ＂hot spots＂ in the landscape. Emissions from the surface soils were significantly higher in the landscape units most freq

关键词： greenhouse gases soil surface water livestock landscape Senegal

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Comparative study of the characterisation and extraction techniques of polyphenolic compounds from Acacia seyal gum

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Food Quality and Safety 2022年第1期6卷 24-33页

作者： Ahmed A.M.Elnour Mohamed E.S.Mirghani Nassereldeen A.Kabbashi Khalid Hamid Musa Fahimeh Shahabipour Nureddin Ashammakhi Nour Hamid Abdurahman International Institute for Halal Research and Training International Islamic University MalaysiaKuala LumpurMalaysia Bioenvironmental Engineering Research Centre Biotechnology Engineering DepartmentKuliyah of EngineeringInternational Islamic University MalaysiaKuala LumpurMalaysia Institute of Gum Arabic&Desertification Studies University of KordofanElobiedSudan Department of Food Science and Human Nutrition College of Agriculture and Veterinary MedicineQassim UniversityBuraydahKingdom of SaudiArabia Skin Research Centre Shahid Beheshti University of Medical SciencesTehranIran Department of Bioengineering Henry Samueli School of EngineeringUniversity of CaliforniaLos AngelesCAUSA Department of Biomedical Engineering College of EngineeringMichigan State UniversityEast LansingMIUSA Centre of Excellence for Advanced Research in Fluid Flow University Malaysia PahangGambangMalaysia

Background Acacia seyal gum(ASG)is an abundant source of natural polyphenolic compounds(NPPCs)and antioxidant activity with numerous benefits and is often used in cancer *** type of extraction technique can significantly impact the yield and isolation of NPPCs from *** traditional use of maceration extraction reportedly yields fewer *** This study investigated five extraction techniques for NPPCs and ASG antioxidant activity,namely:homogenisation,shaking,ultrasonication,magneticstirring,*** and methods The evaluation of the antioxidant activity(AoA)of the extracted NPPCs from ASG used five assays,namely:total flavonoids content,Folin-Ciocalteu index,2,2-diphenyl-1-picrylhydrazyl radical scavenging activity,ferric reducing antioxidant power,and cupric *** To minimise the data set dimensionality requires principal component *** ultrasonic and maceration techniques were the best techniques to extract NPPCs and examine the AoA of ASG,with a high correlation between the NPPCs and ***,the maceration process was slow(12 h)compared to ultrasonication(1 h).Slow extraction can result in a decline of the NPPCs due to polyphenol oxidase-enzyme and impact *** These findings provide an essential guide for the choice of extraction techniques for the effective extraction of NPPCs from ASG and other plant materials.

关键词： Polyphenolic extraction gum Arabic comparison of techniques principal component analysis ultrasonication

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Distribution of central corneal thickness and intraocular pressure in emmetropic eyes of healthy children of Palestine: a representative cross-sectional study

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International Journal of Ophthalmology(English edition) 2019年第3期12卷 496-503页

作者： Hamed Tm Alkhodari Department of Optometry Faculty of Health Sciences Islamic University of Gaza

AIM: To determine the distributions of central corneal thickness(CCT) and intraocular pressure(IOP) in emmetropic eyes of healthy children of ***: This representative cross sectional study included a total of 1156 eyes from 578 healthy school children aged 7-15 y. Inclusion criteria included emmetropia, no previous history of ocular or systemic diseases, no previous history of contact lens use, and the availability of both eyes. CCT and IOP were measured using ultrasound pachymeter and Goldmann applanation tonometer, respectively. The relationship of the results with age and gender was ***: The mean age of school children was 11.13±2.8 y. Mean CCT was 542.2±37.4 and 544.3±39.2 μm for right and left eyes, respectively. Mean IOP was 12.5±2.2 and 12.3±2.2 mm Hg for right and left eyes, respectively. A positive correlation was observed between CCT and IOP of the right eye(P0.05). There were significant differences in mean CCT and IOP between right and left eyes(P=0.004, P=0.001, respectively).CONCLUSION: A population profile of CCT and IOP is established in Palestinian children for the first time. Mean CCT is comparable to some studies but differ from others. Mean IOP is considerably lower than that of majority children of other ethnic groups. Intereye difference of more than 36 μm in CCT, and 5 mm Hg in IOP should prompt evaluation for potential ocular disorders.

关键词： central corneal thickness intraocular pressure intereye asymmetry Goldmann applanation tonometer ultrasound pachymeter

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