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Geospatial characteristics of fire occurrences in southern hemispheric Africa and Madagascar during 2001-2020
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作者 Chuyan Wan Shouraseni Sen Roy 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第2期553-563,共11页
For this study of long-term spatial patterns and trends of active fires in southern hemispheric Africa and on Madagascar from 2001 to 2020,active fire data from the MODIS FIRMS global fire data products were analyzed.... For this study of long-term spatial patterns and trends of active fires in southern hemispheric Africa and on Madagascar from 2001 to 2020,active fire data from the MODIS FIRMS global fire data products were analyzed.The annual center of fire concentration tended to migrate toward the preserved rainforests and nature conservation areas in the Congo Basin and the mountain forests on the northeastern coast of Madagascar.Fire frequency varied seasonally at both study areas.We used geo statistical analysis techniques,such as measures of dispersion and emerging hot spot analysis,to reveal long-term trends in spatial patterns of fire events.In southern hemispheric Africa,the observed active fires tended to drift northward toward the Zambia-DRC border in the Congo basin.This northward migration progressed toward humid rainforests,which were better suited to sustaining repeated fire events.On Madagascar,the observed active fires tended to migrate toward the east coast in protected mountain forests.The spatial patterns of long-term trends showed a concentration of fires in the tropical regions of southern hemispheric Africa.Moreover,smaller clusters of new hot spots were located over eastern South Africa,overlapping with undifferentiated woodlands.On Madagascar,both hot and cold spots were identified and were separated by the highland region in the center of the island.Most of the eastern island was characterized by cold spots that received less precipitation than did the rest of the island.The presence of increasing hots spots in the densely vegetated areas highlights the urgent need for fire prevention and management in this region. 展开更多
关键词 Emerging hot spots analysis FIRMS Forest fi res madagascar MODIS Southern hemispheric Africa Wildfi res
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Digestive Tuberculosis in Madagascar: Histopathological Aspects
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作者 Nomenjanahary Lalaina Rabarison Manoahasina Ranaliarinosy +1 位作者 Rakotonaivo Mamisoa Judicaël Randrianjafisamindrakotroka Nantenaina Soa 《Open Journal of Pathology》 2023年第4期229-234,共6页
Tuberculosis is a contagious infectious disease caused by Mycobacterium tuberculosis complex. This illness is a major public health challenge in Madagascar and around the world. The disease can develop in the lungs an... Tuberculosis is a contagious infectious disease caused by Mycobacterium tuberculosis complex. This illness is a major public health challenge in Madagascar and around the world. The disease can develop in the lungs and other organs. Digestive tuberculosis is rare, accounting for 10% of extrapulmonary forms. Symptoms are not specific. Diagnosis is based on anatomical pathology examination. The purpose of this study is to determine the epidemiological and anatomopathological characteristics of abdominal tuberculosis. Our study was a retrospective, descriptive study conducted at the Pathological Anatomy and Cytology Unit of the University Hospital Center of Joseph Ravoahangy Andrianavalona over a 10-year period from January 1, 2012 to December 31, 2021. Digestive localization accounted for 17 cases, which are 1.85% of extra-pulmonary localizations. The mean age of patients was 33 years with extremes of 9 and 66 years. The sex ratio was 4.67. Pain was the main symptom, accounting for 76.47% of cases. Histological aspects were caseo-follicular in 82.35% (n = 14) of cases, follicular in 11.76% (n = 2) and caseous in 5.89% (n = 1). Patients were treated with isoniazid, rifampicin, pyrazinamide, and ethambutol. Surgery has sometimes been required. Tuberculosis is a public health problem in Madagascar. Digestive localization of the disease is mainly observed in young adults especially among men. Clinical signs are not specific, and diagnosis is based on anatomopathology. Treatment is medical but sometimes surgery may be necessary. 展开更多
关键词 Digestive Tuberculosis Anatomopathology madagascar
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基于Matlab和Madagascar的地震三维图形显示技术研究 被引量:2
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作者 杨志鹏 陈秀清 +2 位作者 陈光容 王登伟 王松 《工程地球物理学报》 2020年第4期426-431,共6页
地震三维图形显示技术作为一项重要的数据可视化手段,在勘探地震学的科研和生产中起到了十分重要的作用。尽管目前已有众多商业地球物理三维可视化软件应用,但在部分科研实验中,往往需将小块地震数据从segy格式转换为mat格式或rsf格式,... 地震三维图形显示技术作为一项重要的数据可视化手段,在勘探地震学的科研和生产中起到了十分重要的作用。尽管目前已有众多商业地球物理三维可视化软件应用,但在部分科研实验中,往往需将小块地震数据从segy格式转换为mat格式或rsf格式,从而在Matlab或Madagascar计算环境下进行理论及算法的验证与开发。在这种情况下,使用庞大的商业软件对小样本数据进行显示会产生内存占用过度或格式频繁转换等问题。为更高效便捷地对三维地震数据进行综合显示,研究了在Matlab和Madagascar两种科研软件下实现地震三维图形显示的技术方法,给出了常用的立体图、切片图、层位图、连井剖面图、展开图等显示方式的核心程序代码。通过示例分析对比证明了本次研究开发的地震三维图形显示技术能够多角度多方面地展示地震数据内部信息,具有较好的应用前景。 展开更多
关键词 MATLAB madagascar 地震数据 三维图形显示
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Origin and Geological Significance of TTG Gneisses from the Maevatanana Greenstone Belt in North-Central Madagascar,and A Comparison with India 被引量:7
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作者 LI Peng LI Jiankang +2 位作者 LIU Shanbao PEI Rongfu SHI Guanghai 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2017年第3期1003-1024,共22页
The Maevatanana greenstone belt in north-central Madagascar contains widespread exposures of tonalite-trondhjemite-granodiorite (TTG) gneisses, and is important for its concentrations of various metal deposits (e.g... The Maevatanana greenstone belt in north-central Madagascar contains widespread exposures of tonalite-trondhjemite-granodiorite (TTG) gneisses, and is important for its concentrations of various metal deposits (e.g., chromium, niekle, iron, gold). In this paper we report on the petrography, and major and trace element compositions of the TTG gneisses within the Berere Complex of the Maevatanana area, as well as LA-ICP-MS U-Pb ages and Lu-Hf isotopic compositions of zircons from the gneisses. The gneisses consist mainly of granitoid gneiss and biotite (± hornblende) plagiogneiss, and analysis of thin sections provides evidence of crushing, recrystallization, and metasomatism related to dynamic metamorphism. Samples have large variations in their major and trace element contents, with SiO2 = 55.87-68.06 wt%, Al2O3 = 13.9-17.8 wt%, and Na2O/K2O= 0.97-2.13. Geochemically, the granitoid gneisses and biotite plagiogneisses fall on a low-Al trondhjemite to granodiorite trend, while the biotite-hornblende plagiogneisses represent a high-Al tonalite TTG assemblage. Zircon U-Pb dating shows that the Berere Complex TTG gneisses formed at 2.5-2.4 Ga. Most εHf(t) values of zircons from the biotite (q- hornblende) plagiogneisses are positive, while most εHf(t) values from the granitoid gneisses are negative, suggesting a degree of crustal contamination. Two-stage Hf model ages suggest that the age of the protolith of the TTG gneisses was ca. 3.4-2.6 Ga, representing a period of paleocontinent formation in the Mesoarchean. Geothermometries indicate the temperature of metamorphism of the TTG gneisses was 522-612℃. Based on these data, the protolith of the TTG gneisses is inferred to have formed during the development of a Mesoarchean paleocontinent that is now widely exposed as a TTG gneiss belt (mostly lower amphibolite facies) in the Maevatanana area, and which records a geological evolution related to the subduction of an ancient oceanic crust and the collision of microcontinents during the formation of the Rodinia supercontinent. The lithological similarity of Precambrian basement, the close ages of metamorphism within greenstone belts and the comparable distribution of metamorphic grade all show a pronounced Precambrian geology similarity between Madagascar and India, which can provide significative clues in understanding the possible Precambrian Supercontinent tectonics, and also important constraints on the correlation of the two continental fragments. 展开更多
关键词 TTG gneiss PETROLOGY GEOCHRONOLOGY Maevatanana greenstone belt madagascar INDIA
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Late syn-to post-collisional magmatism in Madagascar:The genesis of the Ambalavao and Maevarano Suites 被引量:2
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作者 Donnelly B.Archibald Alan S.Collins +3 位作者 John D.Foden Justin L.Payne Peter Holden Théodore Razakamanana 《Geoscience Frontiers》 SCIE CAS CSCD 2019年第6期2063-2084,共22页
The East African Orogen involves a collage of Proterozoic microcontinents and arc terranes that became wedged between older cratonic blocks during the assembly of Gondwana.The Ediacaran-Cambrian Ambalavao and Maevaran... The East African Orogen involves a collage of Proterozoic microcontinents and arc terranes that became wedged between older cratonic blocks during the assembly of Gondwana.The Ediacaran-Cambrian Ambalavao and Maevarano Suites in Madagascar were emplaced during the waning orogenic stages and consist of weakly deformed to undeformed plutonic rocks and dykes of mainly porphyritic granite but also gabbro,diorite and charnockite.U-Pb geochronological data date emplacement of the Ambalavao Suite to between ca.580 Ma and 540 Ma and the Maevarano Suite to between ca.537 Ma and522 Ma.Major and trace element concentrations are consistent with emplacement in a syn-to postcollisional tectonic setting as A-type(anorogenic) suites.Oxygen(δ^(18)O of 5.27‰-7.45‰) and hafnium(ε(Hf)(t) of-27.8 to-12.3) isotopic data from plutons in the Itremo and Antananarivo Domains are consistent with incorporation of an ancient crustal source.More primitive δ^(18)O(5.27‰-5.32‰) andε(Hf)(t)(+0.0 to+0.2) isotopic values recorded in samples collected from the Ikalamavony Domain demonstrate the isotopic variation of basement sources present in the Malagasy crust.The Hf isotopic composition of Malagasy zircon are unlike more juvenile Ediacaran-Cambrian zircon sou rces elsewhere in the East African Orogen and,as such,Madagascar represents a distinct and identifiable detrital zircon source region in Phanerozoic sedimentary provenance studies.Taken together,these data indicate that high-T crustal anatexis,crustal assimilation and interaction of crustal material with mantle-derived melts were the processes operating during magma emplacement.This magmatism was coeval with polyphase deformation throughout Madagascar during the amalgamation of Gondwana and magmatism is interpreted to reflect lithospheric delamination of an extensive orogenic plateau. 展开更多
关键词 madagascar geology East African OROGEN ZIRCON geochronology ZIRCON oxygen and HAFNIUM isotopes POST-COLLISIONAL MAGMATISM
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Modeling impacts of climate change on the potential distribution of six endemic baobab species in Madagascar 被引量:3
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作者 Jun-Nan Wan Ndungu J.Mbari +6 位作者 Sheng-Wei Wang Bing Liu Brian N.Mwangi Jean R.E.Rasoarahona Hai-Ping Xin Ya-Dong Zhou Qing-Feng Wang 《Plant Diversity》 SCIE CAS CSCD 2021年第2期117-124,共8页
Madagascar,a globally renowned biodiversity hotspot characterized by high rates of endemism,is one of the few remaining refugia for many plants and animal species.However,global climate change has greatly affected the... Madagascar,a globally renowned biodiversity hotspot characterized by high rates of endemism,is one of the few remaining refugia for many plants and animal species.However,global climate change has greatly affected the natural ecosystem and endemic species living in Madagascar,and will likely continue to influence species distribution in the future.Madagascar is home to six endemic baobab(Adansonia spp.,Bombacoideae[Malvaceae])species(Adansonia grandidieri,A.suarezensis,A.madagascariensis,A.perrieri,A.rubrostipa,A.za),which are remarkable and endangered plants.This study aimed to model the current distribution of suitable habitat for each baobab species endemic to Madagascar and determine the effect that climate change will have on suitable baobab habitat by the years 2050 and 2070.The distribution was modeled using MaxEnt based on locality information of 245 occurrence sites of six species from both online database and our own field work.A total of seven climatic variables were used for the modeling process.The present distribution of all six Madagascar's baobabs was largely influenced by temperature-related factors.Although both expansion and contraction of suitable habitat are predicted for all species,loss of original suitable habitat is predicted to be extensive.For the most widespread Madagascar baobab,A.za,more than 40%of its original habitat is predicted to be lost because of climate change.Based on these findings,we recommend that areas predicted to contract in response to climate change should be designated key protection regions for baobab conservation. 展开更多
关键词 madagascar Adansonia Climate change MAXENT Potential distribution
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Antiplasmodial,cytotoxic activities and characterization of a new naturally occurring quinone methide pentacyclic triterpenoid derivative isolated from Salacia leptoclada Tul.(Celastraceae)originated from Madagascar 被引量:1
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作者 Fatiany Pierre Ruphin Robijaona Baholy +3 位作者 Randrianarivo Emmanuel Raharisololalao Amelie Marie-Therese Martin Ngbolua Koto-te-Nyiwa 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2013年第10期780-784,共5页
Objective:To validate scientifically the traditional use of Salacia leptoclada Tul.(Celastraceae)(S.leptoclada)and to isolate and elucidate the structure of the biologically active compound.Methods:Bioassay-guided fra... Objective:To validate scientifically the traditional use of Salacia leptoclada Tul.(Celastraceae)(S.leptoclada)and to isolate and elucidate the structure of the biologically active compound.Methods:Bioassay-guided fractionation of the acetonic extract of the stem barks of S.leptoclada was carried out by a combination of chromatography technique and biological experiments in viro using Plasmodium falciparum and P388 leukemia cell lines as models.The structure of the biologically active pure compound was elucidated by 1D and 2D NMR spectroscopy and mass spectrometry.Results:Biological screening of S.leptoclada extracts resulted in the isolation of a pentacyclic triterpenic quinone methide.The pure compound exhibited both in vitro a cytotoxic effect on murine P388 leukemia cells with IC_(50)value of(0.041±0.020)μg/mL and an antiplasmodial activity against the chloroquine-resistant strain FC29 of Plasmodium falciparum with an IC_(50)value of(0.052±0.030)μg/mL.Despite this interesting anti-malarial property of the lead compound,the therapeutic index was weak(0.788).In the best of our knowledge,the quinone methide pentacyclic triterpenoid derivative compound is reported for the first time in S.leptoclada.Conclusions:The results suggest that furthers studies involving antineoplastic activity is needed for the development of this lead compound as anticancer drug. 展开更多
关键词 Salacia leptoclada QUINONE methide MALARIA THERAPEUTIC index Cancer madagascar
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Characteristics and potential analysis of Madagascar hydrocarbon-bearing basins 被引量:2
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作者 Da-tian Wu Johanne Iomimalala Ramaniraka +4 位作者 Feng-ming Xu Jian-bo Shao Yong-heng Zhou Yuan-dong Zhao Bruno Ralison 《China Geology》 2019年第1期56-66,共11页
Madagascar becomes a large isolated island after its dislocation from East Africa at its western part during the opening of the Mozambique Channel and its separation from India at its eastern part during the opening o... Madagascar becomes a large isolated island after its dislocation from East Africa at its western part during the opening of the Mozambique Channel and its separation from India at its eastern part during the opening of the basin of the Mascarene. From a stratigraphic point of view, Karroo of Madagascar shares substantial similarities with the stratigraphic strata of East Africa.While oil companies have taken a liking to the basins of East Africa, they also turn to the basins in the western part of Madagascar especially after the discovery of large oil fields at Tsimiroro and Bemolanga. According to the study of their geological history, the basins of Madagascar contain huge hydrocarbon potential. The western basins, which is more developed than the east coast of the island, have been the subject of many in-depth studies by numerous researchers. The cross-referencing of bibliographic data with geological studies, and knowledge of hydrocarbon formation and maturation stages, carried out in this study served to determine the nature of source rocks, reservoir rocks, bedrock and eventual trapping system of hydrocarbons in Madagascar. This study identified the properties of Madagascar source rocks, reservoir rocks, bedrock and the final oil and gas trap system by cross-referencing the literature and geological research, oil and gas formation and maturity stages, and shows that Madagascar has considerable hydrocarbon potential. 展开更多
关键词 madagascar Hydrocarbon-bearing BASINS CHARACTERISTICS of Malagasy BASINS Potential analysis Geology and STRATIGRAPHY
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Forest aboveground biomass estimates in a tropical rainforest in Madagascar: new insights from the use of wood specific gravity data 被引量:2
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作者 Tahiana Ramananantoandro Herimanitra P.Rafidimanantsoa Miora F.Ramanakoto 《Journal of Forestry Research》 SCIE CAS CSCD 2015年第1期47-55,共9页
To generate carbon credits under the Reducing Emissions from Deforestation and forest Degradation program(REDD+), accurate estimates of forest carbon stocks are needed. Carbon accounting efforts have focused on car... To generate carbon credits under the Reducing Emissions from Deforestation and forest Degradation program(REDD+), accurate estimates of forest carbon stocks are needed. Carbon accounting efforts have focused on carbon stocks in aboveground biomass(AGB).Although wood specific gravity(WSG) is known to be an important variable in AGB estimates, there is currently a lack of data on WSG for Malagasy tree species. This study aimed to determine whether estimates of carbon stocks calculated from literature-based WSG values differed from those based on WSG values measured on wood core samples. Carbon stocks in forest biomass were assessed using two WSG data sets:(i) values measured from 303 wood core samples extracted in the study area,(ii) values derived from international databases. Results suggested that there is difference between the field and literaturebased WSG at the 0.05 level. The latter data set was on average 16 % higher than the former. However, carbon stocks calculated from the two data sets did not differ significantly at the 0.05 level. Such findings could be attributed to the form of the allometric equation used which gives more weight to tree diameter and tree height than to WSG. The choice of dataset should depend on the level of accuracy(Tier II or III) desired by REDD+. As higher levels of accuracy are rewarded by higher prices, speciesspecific WSG data would be highly desirable. 展开更多
关键词 Biomass estimates Carbon stocks Data quality madagascar REDD+ Wood specific gravity
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Attitude survey of nursing students in Madagascar and Japan 被引量:1
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作者 Satomi Kubosawa Narindra Rajaonarison Ny Ony +2 位作者 Maiko Kitajima Yuka Noto Hideaki Yamabe 《Open Journal of Nursing》 2012年第2期79-84,共6页
Background: Few investigations have focused on nursing students from a developing country in relation to a developed country like Japan. Objective: This study explored differences between the nursing students in Madag... Background: Few investigations have focused on nursing students from a developing country in relation to a developed country like Japan. Objective: This study explored differences between the nursing students in Madagascar and Japan. Subjects and Methods: This is a prospective analytical study of 63 nursing students—32 Japanese and 31 Malagasy. Questionnaires were distributed to students in Madagascar and Japan in 2010 and collected for statistical analysis. Results: Malagasy students tended to think that nursing plays a psychological role, and they have positive view for this function. In contrast, Japanese students tended to think that nursing is physical work and they make a point of its outcome and the need for social and economic guarantees. Conclusion: The nursing students in Madagascar and Japan expressed different views and goals. While several factors may be involved in these differences, their distinct medical situations are most likely the major contributor. 展开更多
关键词 madagascar JAPAN NURSING STUDENT Image to NURSE
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Predation Capability of Black Kite (Milvus migrans parasitus) on Locust as a Biological Control Option in Madagascar 被引量:2
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作者 Mahitandrainy Jules Andriatsirevombola Jiwen Ge +1 位作者 Raholijaona 《Open Journal of Ecology》 2016年第5期254-263,共10页
In Madagascar, the South and Southwest regions have for decades had locust outbreaks that have devastated crop fields. The locust species dominant in this area are the red locust (Nomadacris septemfasciata) and the Mi... In Madagascar, the South and Southwest regions have for decades had locust outbreaks that have devastated crop fields. The locust species dominant in this area are the red locust (Nomadacris septemfasciata) and the Migratory Locust (Locusta migratoria capito). This paper aimed at determining the predation values from the Black Kite (Milvus migrans parasitus), a natural enemy for locusts, as a biological measure for locust outbreak control. Two types of experiments were done that included observed predation and experimental predation. It was observed, in the observed predation, that a higher number of locusts were found in the bird’s stomach during the afternoon session (mean = 66) than during the morning session (mean = 21). The high peak observed during the afternoon session was also associated with the feeding of larvae of the migratory locust. The experimental predation results showed that almost 100 percent of the larval and 97 percent of the fledglings were fed on. The experimental predation results also showed that there was no preference for larvae or fledglings in the cage and that the bird fed on the different combinations equally. This study showed that the Black Kite birds can effectively control locust population in an outbreak when they are easy to predate on. However, there is a need to assess the population of birds in locust infested areas to determine if the bird population is enough to predate on a locust outbreak. 展开更多
关键词 Integrated Pest Management Milvus migrans parasitus LOCUST madagascar Avian Insectivory
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Effects of Extracts from Albizia (Fabaceae) Endemic Species of Madagascar on Vegetable Seedling Development 被引量:1
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作者 Danielle Aurore Doll Rakoto Ranjana Randrianarivo Mounidati E1-Yachouroutui Alain A. Arisoa NoelinirinaRaharisoa Noelitiana Rakotondrasoa, Pascaline Raoniharisoa Victor Jeannoda 《Journal of Chemistry and Chemical Engineering》 2012年第4期313-322,共10页
The effects of extracts from five Albizia (Fabaceae) endemic species from Madagascar (A. arenicola, A. boivini, A. bernieri, A. polyphylla and A. tulearensis) were tested on vegetable seedling development. Crude e... The effects of extracts from five Albizia (Fabaceae) endemic species from Madagascar (A. arenicola, A. boivini, A. bernieri, A. polyphylla and A. tulearensis) were tested on vegetable seedling development. Crude extracts were obtained through cold or hot extraction methods on dried powdered seeds, seed teguments, leaves or empty pods. They were thereafter purified using techniques based on physicochemical properties of active substances. Assays were carried out on seedling growth of Monocotyledons and Dicotyledons representatives. Results showed that all extracts exerted significant dose dependent inhibition on epicotyl and hypocotyl growth. However, some extracts exhibited a slight stimulation effect at low doses. Moreover, A. arenicola crude extract (E23) slightly inhibited axillary bud growth, while A. tulearensis crude extract (ET1) showed a stimulation effect. According to preliminary phytochemical screening results, these effects might be due to saponins or alkaloids. 展开更多
关键词 Albizia EXTRACTS SAPONINS ALKALOIDS INHIBITION seedling development madagascar.
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A Proposed Geoheritage Inventory System: Case Study of Isalo National Park, Madagascar 被引量:1
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作者 Hasina N. Randrianaly Andrea Di Cencio +1 位作者 Aroniaina Rajaonarivo Tsilavo Raharimahefa 《Journal of Geoscience and Environment Protection》 2016年第5期163-172,共10页
Geological heritage inventory procedures and templates have been principally emerged from European countries. Each of these countries has developed its proper method of inventory based on its natural heritage, recogni... Geological heritage inventory procedures and templates have been principally emerged from European countries. Each of these countries has developed its proper method of inventory based on its natural heritage, recognized on local and/or regional scales. Natural sites were mainly identified and characterized in a particular geological context, which is usually very unique, valuable and impressive;resulting in the protection of the sites. Madagascar is known internationally as a beautifully landscaped island, but the impressive sites were not cataloged. We carried out a series of field inventory of potential geological sites within the Isalo National Park in southern Madagascar. We invented several inventory sheets in order to record the most detailed information about the sites identified within the park. This is to aid in organizing the park and to establish a sustainable base for the creation of a geopark, and also they help us to build a database for geosites and their classifications. This article suggests a prototype model for inventorying intangible geosites, paleosites and geomorphosites. Our inventory sheets help to identify and to promote geological importance of any sites, not only for academia but also for other sectors such as tourism and conservation. 展开更多
关键词 Inventory Sheets GEOHERITAGE Geosites Paleosites Geomorphosites Park National Isalo Park madagascar
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Petrogenesis of the Ambohiby Complex Madagascar and the Role of the Marion Hotspot
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作者 N.C.Mukosi Ja Miller Ph Macey 《地学前缘》 EI CAS CSCD 北大核心 2009年第S1期211-211,共1页
The Cretaceous Ambohiby Complex is an alkaline ring complex located in the west central part of Madagascar and covers a mountainous area of approximate 225 km^2.The complex intrudes into Precambrian basement gneisses ... The Cretaceous Ambohiby Complex is an alkaline ring complex located in the west central part of Madagascar and covers a mountainous area of approximate 225 km^2.The complex intrudes into Precambrian basement gneisses and is dominated by alkaline mafic to felsic rocks with sodic mineralogies. Pyroxenes are generally aegirine,aegirine-augite,and hedenbergite and commonly occur in granites, 展开更多
关键词 Ambohiby COMPLEX madagascar Marion HOTSPOT PETROGENESIS GONDWANA
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Cordierite-bearing granulites from Ihosy,southern Madagascar:Petrology,geochronology and regional correlation of suture zones in Madagascar and India
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作者 Li Tang Meng Pan +3 位作者 Toshiaki Tsunogae Yusuke Takamura Yukiyasu Tsutsumi N.O.T.Rakotonandrasana 《Geoscience Frontiers》 SCIE CAS CSCD 2019年第6期2007-2019,共13页
Madagascar,a major fragment of Gondwana,is mainly composed of Precambrian basenent rocks formed by Mesoarchean to Neoproterozoic tectono-thernial events and recording a Pan-African metamorphic overprint.The Ranotsara ... Madagascar,a major fragment of Gondwana,is mainly composed of Precambrian basenent rocks formed by Mesoarchean to Neoproterozoic tectono-thernial events and recording a Pan-African metamorphic overprint.The Ranotsara Shear Zone in southern Madagascar has been correlated with shear zones in southern India and eastern Africa in the reconstruction of the Gondwana supercontinent.Here we present detailed petrology,mineral chemistry,metamorphic P-T constraints using phase equilibrium modelling and zircon U-Pb geochronological data on high-grade metamorphic rocks from Ihosy within the Ranotsara Shear Zone.Garnet-cordierite gneiss from Ihosy experienced two stages of metamorphism.The peak mineral assemblage is interpreted as garnet+sillimanite+cordierite+quartz+plagioclase+Kfeldspar+magnetite+spinel+ilmenite,which is overprinted by a retrograde mineral assemblage of biotite+garnet+cordierite+quartz+plagioclase+K-feldspar+magnetite+spinel+ilmenite.Phase equilibria nodelling in the system Na2 O-CaO-K2 O-FeO-MgO-Al2 O3-SiO2-H2 O-TiO2-Fe2 O3(NCKFMASHTO)indicates peak metamorphic conditions of 850-960℃ and 6.9-77 kbar,and retrograde P-Tconditions of<740℃ and<4.8 kbar,that define a clockwise P-T path.Near-concordant ages of detrital zircon grains in the garnet-cordierite gneiss dominantly exhibit ages between 2030 Ma and 1784 Ma,indicating dominantly Paleoproterozoic sources.The lower intercept age of 514±33 Ma probably indicates the timing of high-grade metamorphism,which coincides with the assembly of the Gondwana supercontinent.The comparable rock types,zircon ages and metamorphic P-T paths between the Ranotsara Shear Zone and the Achankovil Suture Zone in southern India support an interpretation that the Ranotsara Shear Zone is a continuation of the Achankovil Suture Zone. 展开更多
关键词 PSEUDOSECTION modelling Cordierite-bearing granulite Detrital zircon GEOCHRONOLOGY madagascar Gondwana SUPERCONTINENT
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Probabilistic Modelling of COVID-19 Dynamic in the Context of Madagascar 被引量:1
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作者 Angelo Raherinirina Tsilefa Stefana Fandresena +3 位作者 Aimé Richard Hajalalaina Haja Rabetafika Rivo Andry Rakotoarivelo Fontaine Rafamatanantsoa 《Open Journal of Modelling and Simulation》 2021年第3期211-230,共20页
We propose a probabilistic approach to modelling the propagation of the coronavirus disease 2019 (COVID-19) in Madagascar, with all its specificities. With the strategy of the Malagasy state, which consists of isolati... We propose a probabilistic approach to modelling the propagation of the coronavirus disease 2019 (COVID-19) in Madagascar, with all its specificities. With the strategy of the Malagasy state, which consists of isolating all suspected cases and hospitalized confirmed case, we get an epidemic model with seven compartments: susceptible (S), Exposed (E), Infected (I), Asymptomatic (A), Hospitalized (H), Cured (C) and Death (D). In addition to the classical deterministic models used in epidemiology, the stochastic model offers a natural representation of the evolution of the COVID-19 epidemic. We inferred <span><span style="font-family:Verdana;">the models with the official data provided by the COVID-19 Command Center (CCO) of Madagascar, between March and August 2020. The basic reproduction number <i></i></span><i><i><span style="font-family:Verdana;">R<sub></sub></span></i></i></span><i><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;"><sub>0</sub></span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><i><span style="font-family:Verdana;"></span></i></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"></span></span></span></i> and the other parameters were estimated with a Bayesian approach. We developed an algorithm that allows having a temporal estimate of this number with confidence intervals. The estimated values are slightly lower than the international references. Generally, we were able to obtain a simple but effective model to describe the spread of the disease. 展开更多
关键词 Modified SEIR Model COVID-19 madagascar Basic Reproduction Number Markov Chain Continuous Time
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Crystallographic Study of Uranium-Thorium Bearing Minerals in Tranomaro,South-East Madagascar 被引量:1
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作者 Frank Elliot Sahoa Naivo Rabesiranana +3 位作者 Raoelina Andriambololona Nicolas Finck Christian Marquardt Hörst Geckeis 《Journal of Minerals and Materials Characterization and Engineering》 2013年第6期347-352,共6页
Studies are undertaken to characterize the uranium and thorium minerals of south-east Madagascar. Seven selected uranothorianite bearing pyroxenites samples from old abandoned uranium quarries in Tranomaro, south Ambo... Studies are undertaken to characterize the uranium and thorium minerals of south-east Madagascar. Seven selected uranothorianite bearing pyroxenites samples from old abandoned uranium quarries in Tranomaro, south Amboasary, Madagascar (46°28'00"E, 24°36'00"S) have been collected. To determine the mineral micro-structure, they were investigated for qualitative identification of crystalline compounds by using X-ray powder diffraction analytical method (XRD). Results showed that the uranium and thorium compounds, as minor elements, were present in various crystalline structures. Thorium, as thorianite, is present in a simple ThO2 cubic crystalline system, whereas the uranium component of the Tranomaro uranothorianite samples is oxide-based and is a mixture of complex oxidation states and crys-talline systems. Generally called uraninite, its oxide compounds are present in more than eight phases. 展开更多
关键词 Tranomaro madagascar Uranothorianite CRYSTALLOGRAPHY XRD
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Isolation and structural elucidation of cytotoxic compounds from the root bark of Diospyros quercina (Baill.) endemic to Madagascar
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作者 Fatiany Pierre Ruphin Robijaona Baholy +3 位作者 Randrianarivo Emmanuel Raharisololalao Amelie Marie-Therese Martin Ngbolua Koto-te-Nyiwa 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2014年第3期169-175,共7页
Objective:To isolate and characterize the cytotoxic compounds from Diospyros quercina(Baill.)G.E.Schatz&Lowry(Ebenaceae).Methods:An ethno-botanical survey was conducted in the south of Madagascar from July to Augu... Objective:To isolate and characterize the cytotoxic compounds from Diospyros quercina(Baill.)G.E.Schatz&Lowry(Ebenaceae).Methods:An ethno-botanical survey was conducted in the south of Madagascar from July to August 2010.Bio-guided fractionation assay was carried out on the root bark of Diospyros quercina,using cytotoxicity bioassay on murine P388 leukemia cell lines as model.The structures of the cytotoxic compounds were elucidated by 1D and 2D NMR spectroscopy and mass spectrometry.Results:Biological experiments resulted in the isolation of three bioactive pure compounds(named TR-21,TR-22,and TR-23)which exhibited very good in vitro cytotoxic activities with the IC_(50)values of(0.017 5±0.0060)μg/mL,(0.089±0.005)μg/mL and(1.027±0.070)μg/mL respectively.Thus,they support the claims of traditional healers and suggest the possible correlation between the chemical composition of this plant and its wide use in Malagasy folk medicine to treat cancer.Conclusions:The ability of isolated compounds in this study to inhibit cell growth may represent a rational explanation for the use of Diospyros quercina root bark in treating cancer by Malagasy traditional healers.Further studies are,therefore,necessary to evaluate the in vivo antineoplastic activity of these cytotoxic compounds as effective anticancer drugs. 展开更多
关键词 DIOSPYROS quercinia Cytotoxic activities Isodiospyrin 6’-Ethoxy-1’ 3’-dihydroxy-4 6-dimethyl-1 2’-binaphthyl-2 5’3 8’tetraones (E)-5 6-Dimethyl-2-(2-methyl-3-(prop-1-enyl) phenyl)-2H-Chromene madagascar
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Whither the Community? Lessons Madagascar Can Learn from Israel’s Water Policy
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作者 Richard R. Marcus 《Journal of Water Resource and Protection》 2012年第10期812-830,共19页
Madagascar wrote a fundamentally new Water Code in 1998. It focused on maximizing the number of people with access to clean water through a process of decentralized water management and cost recovery. This paper is co... Madagascar wrote a fundamentally new Water Code in 1998. It focused on maximizing the number of people with access to clean water through a process of decentralized water management and cost recovery. This paper is concerned with the policy problem this presents at the community level—is Malagasy water law the best possible for the country? Combining community-level focus group studies and policy analysis, this study examines Malagasy water policy shifts focusing on localization of water governance to parallel localization efforts in Israel. This study concludes that Madagascar’s water policy is flawed. Using a case study from the arid south this study explores the impact of these alternatives to ineffective state-centric policies. Comparing to Israel’s policy process this study finds that the Malagasy policy process has not been a process at all, the institutions are not in place, and the requisite levels of investment are not forthcoming. Rather than empowering communities as stewards of their own resources, community level management has been undermining effective governance by allowing the state to recede, and minimizing economic resources, while ignoring local capacity, local will, and increasing local water poverty. 展开更多
关键词 madagascar Israel WATER POLICY
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Mapping of groundwater potential zones in the drought-prone areas of south Madagascar using geospatial techniques
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作者 Charles Serele Ana Perez-Hoyos Francois Kayitakire 《Geoscience Frontiers》 SCIE CAS CSCD 2020年第4期1403-1413,共11页
The southern regions of Madagascar have the country’s lowest water supply coverage and are highly vulnerable to drought.Access to potable drinking water is a major challenge for the local population.Chronic droughts ... The southern regions of Madagascar have the country’s lowest water supply coverage and are highly vulnerable to drought.Access to potable drinking water is a major challenge for the local population.Chronic droughts lead to annual emergency appeals to save the lives of acute malnourished children.UNICEF’s response consisting in providing potable drinking water through the drilling of boreholes has been challenged by the complex hydrogeology,the low yield of boreholes and high-level salinity of water,the lack of reliable groundwater data and the weak capacity of the drilling sector.These constraints result in a high rate of drilling failure.To improve drilling success and provide more potable drinking water to local communities,it is vital to undertake reliable groundwater investigation.UNICEF Madagascar and the European Union delegation in Madagascar collaborated on the use of satellite imagery to improve sector knowledge and access to safe and clean water for local communities in southern Madagascar.The methodology relies on produce thematic layers of groundwater potential areas.Later,these thematic layers were overlaid with ground-based hydrogeological data to map the groundwater potential zones(GWP) and identify the most suitable sites for borehole siting and drilling.Findings of this study are very encouraging,and the integrated approach used has proven its applicability in mapping groundwater potential areas in the eight drought-affected areas of south Madagascar.The groundwater potential zone map is being used by UNICEF and partners to plan water supply projects and identify the best sites for positioning new boreholes and reduce the likelihood of drilling failure.Additionally,the project developed a database of groundwater resources,which will improve knowledge of the regional hydrogeological context and strengthen the capacity of the water sector.Lessons learnt from this study show that an integration of the groundwater potential zone map with demographics and water demand information will help identifying priority areas for detailed studies.Moreover,a capacity building activity is required for knowledge/technology transfer to the Ministry of Energy,Water and Hydrocarbons(MEEH),allowing the possibility of scaling-up this integrated approach to the rest of Madagascar.Finally,strengthening the capacity of the MEEH and refining this approach as suggested above will certainly help in the pursuit to improve equitable access to safe and clean water for households located in the drought-affected areas of southern Madagascar,allowing them to be more resilient to the effects of climate change. 展开更多
关键词 Groundwater potential zones(GWP) Overlay analysis Remote sensing Geographic information system(GIS) South madagascar
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