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Geospatial Variability of Cholera Cases in Malawi Based on Climatic and Socioeconomic Influences

Journal of Geographic Information System 2024年第1期16卷 1-20页

作者： Emmanuel Chinkaka francis Chauluka Ruth Chinkaka Billy Kachingwe Esther Banda Latif department of Geography and Spatial sciences University of Delaware Newark USA department of earth sciences Malawi University of Science and Technology Limbe Malawi department of Water Resources Management Malawi University of Science and Technology Limbe Malawi department of Obstetrics and Gynecology Queen Elizabeth Central Hospital Blantyre Malawi department of Public Health Nkhoma Mission Hospital Nkhoma Malawi

Cholera remains a public health threat in most developing countries in Asia and Africa including Malawi with seasonal recurrent outbreaks. Malawi’s recent Cholera outbreak in 2022 and 2023, exhibited higher morbidity and mortality rates than the past two decades. Lack of spatiotemporal-based technology and variability assessment tools in Malawi’s Cholera monitoring and management, limit our understanding of the disease’s epidemiology. The present work developed a spatiotemporal variability model for Cholera disease at district level and its relationship to socioeconomic and climatic factors based on cumulative confirmed Cholera cases in Malawi from March 2022 to July 2023 using Z-score statistic and multiscale geographically weighted regression (MGWR) in a Geographical Information System (GIS). We found out that socioeconomic factors such as access to safe drinking water, population density and poverty level, and climatic factors including temperature and rainfall strongly influenced Cholera prevalence in a complex and multifaceted manner. The model shows that Lilongwe, Mangochi, Blantyre and Balaka districts were highly vulnerable to Cholera disease followed by lakeshore districts of Salima, Nkhotakota, Nkhata-Bay and Karonga than other districts. We recommend strategic measures such as Water, Sanitation, and Hygiene (WASH) interventions, community awareness on proper water storage, Cholera case management, vaccination campaigns and spatial-based surveillance systems in the most affected districts. This research has shown that MGWR, as a surveillance system, has the potential of providing insights on the disease’s spatial patterns for public health authorities to identify high-risk districts and implement early response interventions to reduce the spread of the disease.

关键词： Cholera Geospatial Variability Prevalence GIS MGWR Vulnerability Malawi

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Assessing the utility of dissolved organic matter photoreactivity as a predictor of in situ methylmercury concentration

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Journal of Environmental sciences 2018年第6期30卷 160-168页

作者： Sara J.Klapstein Susan E.Ziegler David A.Risk Nelson J.O'Driscoll Environmental Science Program Memorial University of Newfoundland department of earth sciences St. Francis Xavier University department of earth and Environmental Science Acadia University

Methylmercury（MeHg） bioaccumulation is a growing concern in ecosystems worldwide. The absorption of solar radiation by dissolved organic matter（DOM） and other photoreactive ligands can convert MeHg into less toxic forms of mercury through photodemethylation. In this study, spectral changes and photoreactivity of DOM were measured to assess the potential to control photoreactions and predict in situ MeHg concentration. Water samples collected from a series of lakes in southwestern Nova Scotia in June, August, and September were exposed to controlled ultraviolet-A（UV-A） radiation for up to 24 hr. Dissolved organic matter photoreactivity, measured as the loss of absorbance at 350 nm at constant UV-A irradiation, was positively dependent on the initial DOM concentration in lake waters（r^2=0.94）. This relationship was consistent over time with both DOM concentration and photoreactivity increasing from summer into fall across lakes. Lake in situ MeHg concentration was positively correlated with DOM concentration and likely catchment transport in June（r = 0.77） but not the other sampling months. Despite a consistent seasonal variation in both DOM and Fe, and their respective correlations with MeHg, no discernable seasonal trend in MeHg was observed. However, a 3-year dataset from the 6 study lakes revealed a positive correlation between DOM concentration and both Fe（r = 0.91） and MeHg concentrations（r = 0.51） suggesting a more dominant landscape mobility control on *** DOM-MeHg relationships observed in these lakes highlights the need to examine DOM photoreactivity controls on MeHg transport and availability in natural waters particularly given future climate perturbations.

关键词： Methylmercury Dissolved organic carbon Photoreactions Kejimkujik National Park Freshwater lakes

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Speculations on the mechanisms for the formation and breakup of supercontinents

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Geoscience Frontiers 2013年第2期4卷 185-194页

作者： J.Brendan Murphy R.Damian Nance department of earth sciences.st.francis xavier university Antigonish.Nova Scotia B2G 2W5Canada department of Geological sciences Ohio UniversityAthensOH 45701USA

The supercontinent cycle has had a profound effect on the earth＇s evolution since the Late Archean but our understanding of the forces responsible for its operation remains *** appear to form by two end-member processes：extroversion,in which the oceanic lithosphere surrounding the supercontinent（exterior ocean） is preferentially subducted（***）,and introversion in which the oceanic lithosphere formed between dispersing fragments of the previous supercontinent（interior ocean） is preferentially subducted（***）.Extroversion can be explained by ＂top-down＂ geodynamics, in which a supercontinent breaks up over a geoid high and amalgamates above a geoid low. Introversion,on the other hand,requires that the combined forces of slab-pull and ridge push（which operate in concert after supercontinent break-up） must be overcome in order to enable the previously dispersing continents to turn *** may begin when subduction zones are initiated along boundaries between the interior and exterior oceans and become trapped within the interior *** speculate that the reversal in continental motion required for introversion may be induced by slab avalanche events that trigger the rise of superplumes from the core-mantle boundary.

关键词： Supercontinent cycle Introversion Extroversion Pangea Rodinia Pannotia

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Enhanced detection of freeze‒thaw induced landslides in Zhidoi county(Tibetan Plateau,China)with Google earth Engine and image fusion

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Advances in Climate Change Research 2024年第3期15卷 476-489页

作者： Jia-Hui YANG Yan-Chen GAO Lang JIA Wen-Juan WANG Qing-Bai WU francis ZVOMUYA Miles DYCK Hai-Long HE College of Natural Resources and Environment Northwest A&F UniversityYangling 712100China state Key Laboratory of Frozen Soil Engineering Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China department of Soil Science University of Manitob1Winnipeg MB R3T 2N2Canada department of Renewable Resources University of Albert1Edmonton AB T6G 2H1Canad

Freeze‒thaw induced landslides(FTILs)in grasslands on the Tibetan Plateau are a geological disaster leading to soil *** landslides reduce biodiversity and intensify landscape fragmentation,which in turn are strengthen by the persistent climate change and increased anthropogenic ***,conventional techniques for mapping FTILs on a regional scale are impractical due to their labor-intensive,costly,and time-consuming *** study focuses on improving FTILs detection by implementing image fusion-based Google earth Engine(GEE)and a random forest *** of multiple data sources,including texture features,index features,spectral features,slope,and vertical‒vertical polarization data,allow automatic detection of the spatial distribution characteristics of FTILs in Zhidoi county,which is located within the Qinghai‒Tibet Engineering Corridor(QTEC).We employed statistical techniques to elucidate the mechanisms influencing FTILs *** enhanced method identifies two schemes that achieve high accuracy using a smaller training sample(scheme A:94.1%;scheme D:94.5%)compared to other methods(scheme B:50.0%;scheme C:95.8%).This methodology is effective in generating accurate results using only~10%of the training sample size necessitated by other *** spatial distribution patterns of FTILs generated for 2021 are similar to those obtained using various other training sample sources,with a primary concentration observed along the central region traversed by the *** results highlight the slope as the most crucial feature in the fusion images,accounting for 93%of FTILs occurring on gentle slopes ranging from 0°to 14°.This study provides a theoretical framework and technological reference for the identification,monitoring,prevention and control of FTILs in *** developments hold the potential to benefit the management of grassland ecosystem,reduce economic losses,and promote grassland sustainability.

关键词： Permafrost degradation Random forest Thaw slump Spatial distribution Tibetan Plateau

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Origins of the supercontinent cycle

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Geoscience Frontiers 2013年第4期4卷 439-448页

作者： R.Damian Nance J.Brendan Murphy department of Geological Sciences.316 Clippinger Laboratories.Ohio University.Athens.OH 45701.USA department of earth sciences st.Francis Xavier UniversityAntigonishNova Scotia B2G 2W5.Canada

The supercontinent cycle, by which earth history is seen as having been punctuated by the episodic assembly and breakup of supercontinents, has influenced the rock record more than any other geologic phenomena, and its recognition is arguably the most important advance in earth Science since plate tectonics. It documents fundamental aspects of the planet＇s interior dynamics and has charted the course of earth＇s tectonic, climatic and biogeochemical evolution for billions of years. But while the widespread realization of the importance of supercontinents in earth history is a relatively recent development, the supercontinent cycle was first proposed thirty years ago and episodicity in tectonic processes was recognized long before plate tectonics provided a potential explanation for its occurrence. With interest in the supercontinent cycle gaining momentum and the literature expanding rapidly, it is instructive to recall the historical context from which the concept developed. Here we examine the supercontinent cycle from this perspective by tracing its development from the early recognition of long-term epi- sodicity in tectonic processes, through the identification of tectonic cycles following the advent of plate tectonics, to the first realization that these phenomena were the manifestation of episodic superconti- nent assembly and breakup.

关键词： Supercontinent cyclePlate tectonicstectonic episodicitySecular trends

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Trial by fire:Testing the paleolongitude of Pangea of competing reference frames with the African LLSVP

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Geoscience Frontiers 2020年第4期11卷 1253-1256页

作者： Ross N.Mitchell Lei Wu J.Brendan Murphy Zheng-Xiang Li state Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijingChina earth Dynamics Research Group The Institute for Geoscience Research(TIGeR)School of Earth and Planetary SciencesCurtin UniversityGPO Box U1987PerthWAAustralia department of earth sciences St.Francis Xavier UniversityAntigonishNova ScotiaCanada

Paleogeography can be reconstructed using various crust-or mantle-based reference frames that make fundamentally different *** various reconstruction models differ significantly in continental paleolongitude,but it has been difficult to assess which models are more *** suggest here a "LLSVP test",where an assumed correlation between present-day large low velocity shear-wave provinces and the paleogeography of supercontinent Pangea at breakup ca.200 million years ago can be used to assess the relative accuracy of published *** correlations between continental paleolongitude and the African LLSVP are achieved with mantle-based reference frames(moving hotspots and true polar wander),whereas shallower crustbased reference frames are shown to be *** relative success of mantle-based frames,and thus the importance of the depth of reference frame,supports the notion that mantle convection is largely vertical compared to the horizontal plate motion of tectonics.

关键词： Palaeogeography Plate tectonics LLSVPs Reference frames

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Breccia-cored columnar rosettes in a rubbly pahoehoe lava flow,Elephanta Island,Deccan Traps,and a model for their origin

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地学前缘：英文版 2017年第6期8卷 1299-1309页

作者： Hetu Sheth Ishita Pal Vanit Patel Hrishikesh Samant Joseph D'Souza department of earth sciences Indian Institute of Technology Bombay(IITB) Institute of Geophysics and Planetary Physics Scripps Institution of OceanographyUniversity of California San Diego department of Geology St.Xavier's College

Rubbly pahoehoe lava flows are abundant in many continental flood basalts including the Deccan ***,structures with radial joint columns surrounding cores of flow-top breccia(FTB),reported from some Deccan rubbly pahoehoe flows,are yet unknown from other basaltic provinces.A previous study of these Deccan "breccia-cored columnar rosettes" ruled out explanations such as volcanic vents and lava tubes,and showed that the radial joint columns had grown outwards from cold FTB inclusions incorporated into the hot molten *** the highly vesicular(thus low-density)FTB blocks might have sunk into the flow interiors has remained a *** we describe a new example of a Deccan rubbly pahoehoe flow with FTB-cored rosettes,from Elephanta Island in the Mumbai *** that(1)thick rubbly pahoehoe flows probably form by rapid inflation(involving many lava injections into a largely molten advancing flow),and(2)such flows are transitional to 'a'a flows(which continuously shed their top clinker in front of them as they advance),we propose a model for the FTB-cored *** suggest that the Deccan flows under study were shedding some of their FTB in front of them as they advanced and,with high-eruption rate lava injection and inflation,frontal breakouts would incorporate this FTB rubble,with thickening of the flow carrying the rubble into the flow *** implies that,far from sinking into the molten interior,the FTB blocks may have been rising,until lava supply and inflation stopped,the flow began solidifying,and joint columns developed outward from each cold FTB inclusion as already inferred,forming the FTB-cored *** rubbly pahoehoe flows which began recycling most of their FTB became the 'a'a flows of the Deccan.

关键词： Rubbly pahoehoe Columnar jointing Flow-top breccia Volcanism Flood basalt Deccan Traps

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A field parcel-oriented approach to evaluate the crop cover-management factor and time-distributed erosion risk in Europe

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International Soil and Water Conservation Research 2023年第1期11卷 43-59页

作者： francis Matthews Gert Verstraeten Pasquale Borrelli Panos Panagos European Commission Joint Research Centre(JRC)IspraItaly department of earth and Environmental sciences KU LeuvenBelgium department of Science Roma Tre University00146RomeItaly

The crop cover-management(C-)factor in arable landscapes describes the soil erosion susceptibility associated with seasonally cultivated *** informatic and computational limitations have led many modelling studies to prescribe C-factor values and assume spatial and temporal ***,the multiple influencing factors ranging from parcel-scale crop cultivation and management to regional-scale rainfall regimes motivates new methods to capture this variation when identifying at-risk ***,we define a multi-component method to derive the C-factor by associating time series of canopy and residue surface cover from Sentinel-2 and climate-specific rainfall erosivity with Integrated Administration and Control System(IACS)field parcel data from European Union member states.A scalable and standardised method is emphasised to increase the future interoperability and inter-comparability of soil erosion modelling studies deploying the ***,field parcel simu-lation units with associated crop declarations provide a new reference scale to link predictions of soil erosion risk with specific management decisions and declarations by *** implementing the method on a homogenised subsample of 8600 field parcels covering available IACS regions,several key findings are outlined:1)time series information provides new opportunities to predict the time-criticality of erosion in specific crop cultivations,2)the varying(a-)synchronicity between seasonal crop canopy cover and heavy rainstorms means that spatial variability is inherent within the C-factor across Europe,and 3)the addition of agricultural management practices(*** practice de-scriptions)to open-access IACS repositories can facilitate more comprehensive evaluations of the C-factor and soil erosion risk.

关键词： C-factor Soil erosion Modelling Remote sensing Crop-phenology IACS data Soil conservation Europe

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Biostratigraphy and geography of the Ordovician-Silurian Lungmachi black shales in South China

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Science China earth sciences 2011年第12期54卷 1854-1863页

作者： FAN JunXuan Michael J MELCHIN CHEN Xu WANG Yi ZHANG YuanDong CHEN Qing CHI ZhaoLi CHEN Feng state Key Laboratory of Palaeobiology and stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China department of earth sciences St. Francis Xavier University Antigonish Nova Scotia B2G 2W5 Canada Algeria Branch of International Oil and Development Company SINOPEK Dongying 257000 China

Based on the new material of seven Ordovician-Silurian boundary sections investigated recently, together with previously published data, we analyze the temporal and spatial distributions of the Lungmachi black shales, a key petroleum source bed widely distributed in South China. The Lungmachi black shales range in age from the Normalograptus persculptus Biozone of the uppermost Ordovician to the Spirograptus guerichi Biozone of the lower Telychian, and ten graptolite biozones can be recognized within this unit. The basal and upper contacts of the Lungmachi black shales are diachronous. The basal contact ranges from the N. persculptus to the C. cyphus biozones, a span of five graptolite biozones over two stages. The upper contact ranges from the D. pectinatus-M. argenteus Biozone to the Spirograptus guerichi Biozone, which spans four graptolite biozones over two stages. The Yichang Uplift resulted in the formation of the Hunan-Hubei Submarine High in the border area of Hubei, Hunan, and Chongqing. This is supported by a break in sedimentation in this area spanning all or part of the Hirnantian, and in many areas extending into the underlying Katian and overlying Rhuddanian. Comparison of the distribution of the Katian to Rhuddanian strata in this area indicates a growth and subsequent reduction in area of the Hunan-Hubei Submarine High particularly in the Hirnantian to early Rhuddanian. This may partly represent the influence of the process of formation and melting of ice sheet in Ordovician South Pole and consequent sea level change.

关键词：黑色页岩中国南方地层学志留系地理海平面变化生物带空间分布

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Late syn-to post-collisional magmatism in Madagascar:The genesis of the Ambalavao and Maevarano Suites

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Geoscience Frontiers 2019年第6期10卷 2063-2084页

作者： Donnelly B.Archibald Alan S.Collins John D.Foden Justin L.Payne Peter Holden Théodore Razakamanana department of earth sciences St.Francis Xavier UniversityPhysical Sciences Complex5009 Chapel SquareAntigonishNSB2G 2W5Canada Centre for Tectonics Resources and Exploration(TRaX)Department of Earth SciencesThe University of AdelaideAdelaide 5005SAAustralia Centre for Tectonics Resources and Exploration(TRaX)School of Built and Natural EnvironmentsUniversity of South AustraliaMawson LakesSA5001Australia Research School of earth sciences The Australian National UniversityCanberraACT2601Australia Departement des sciences de la Terre Universitede ToliaraToliara601Madagascar

The East African Orogen involves a collage of Proterozoic microcontinents and arc terranes that became wedged between older cratonic blocks during the assembly of *** 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 *** and trace element concentrations are consistent with emplacement in a syn-to postcollisional tectonic setting as A-type(anorogenic) ***(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 *** 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 *** 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 *** 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 *** 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.

关键词： Madagascar geology East African orogen Zircon geochronology Zircon oxygen and hafnium isotopes Post-collisional magmatism

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