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Zircon U-Pb and Lu-Hf isotope constraints on Archean crustal evolution in Southeastern guyana Shield

Geoscience Frontiers 2019年第4期10卷 1477-1506页

作者： Joao Marinho Milhomem Neto Jean-Michel Lafon Programa de Pos-graduacao em Geologia e Geoquimica-PPGG Instituto de Geociencias-IGUniversidade Federal do Para-UFPA66075-110BelemParaBrazil Laboratório de Geologia Isotópica-Pará-Iso IG-UFPA66075-110BelémParáBrazil

The southeastern guyana Shield,northeast Amazonian Craton,in the north of Brazil,is part of a widespread orogenic belt developed during the Transamazonian orogenic cycle(2.26-1.95 Ga)that includes a large Archean continental landmass strongly reworked during the Transamazonian orogeny,named Amapa *** consists mainly of a high-grade metamorphic granulitic-migmatitic-gneiss complex,of Meso-to Neoarchean age and Rhyacian granitoids and supracrustal *** the first time,coupled U-Pb and Lu-Hf isotope data were obtained on zircon by LA-ICP-MS from five tectono-stratigraphic units of the Archean basement and one Paleoproterozoic intrusive rock,in order to investigate the main episodes of crustal growth and ***-rock Sm-Nd isotope data were compared to the zircon Lu-Hf *** main magmatic episodes were defined by U-Pb zircon dating,two in the Mesoarchean(~3.19 Ga and 2.85 Ga)and one in the Neoarchean(~2.69-2.65 Ga).SubchondriticεHf(t)values obtained for almost all investigated units indicate that crustal reworking processes were predominant during the formation of rocks that today make up the Amapa ***-TDMC model ages,ranging from2.99 Ga to 3.97 Ga,indicate that at least two important periods of mantle extraction and continental crust formation occurred during the Archean in southeastern guyana Shield,an older one in the Eoarchean(~4.0 Ga)and a younger one in the Mesoarchean(~3.0-3.1 Ga).The latter is recognized as an important period of crustal accretion *** recognition of an Eoarchean episode to the southeastern most part of the guyana Shield is unprecedented and was not recorded by whole-rock Sm-Nd data,which were restricted to the Meso-Paleoarchean(2.83 Ga to 3.51 Ga).This finding reveals t hat continental crust generation in the Amazonian Craton began at least 500 Ma earlier than previously suggested by the SmNd systematics.

关键词： U-Pb-Lu-Hf isotopes Zircon Archean crustal evolution Southeastern guyana Shield Amazonian Craton

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Building capabilities in natural resource-dependent economies:An innovation systems analysis of the TVET program in guyana

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International Journal of Innovation Studies 2019年第1期3卷 1-11页

作者： Chantal Dos Santos Friedrich-Alexander University Erlangen-Nuremberg 91054 ErlangenGermany

This paper examines guyana's technical and vocational education and training(TVET)system in relation to diversifying the country's economy away from natural resource *** innovation systems approach is used to examine the effectiveness of TVET as a means of building capabilities in guyana's key industries,gold and sugar,providing a snapshot of the state of the system in early,*** interviewees across several areas of expertise were consulted in Georgetown,*** analysis of primary and secondary research finds TVET's effectiveness to be limited by a lack of labor market information and funding,energy costs,a“brain drain”,and insufficient information communication technology skills and *** remedies include increasing the frequency of labor market surveys,attracting the Guyanese diaspora back to share knowledge,reducing the cost of energy by taking advantage of domestic renewable energy potential,and setting up a Sovereign Wealth Fund.

关键词： Innovation systems guyana CARICOM Natural resources TVET

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Prevalence of Cesarean Section at Georgetown Public Hospital Corporation, guyana: An Institution-Based Cross-Sectional Study

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Open Journal of Clinical Diagnostics 2023年第3期13卷 29-47页

作者： Gary Joseph Cecil Boston Gbenankpon Mathias Houvessou Georgetown Public Hospital Corporation Georgetown Guyana College of Medical Sciences University of Guyana Georgetown Guyana Department of Environmental Medicine and Public Health Icahn School of medicine at Mount Sinai New York USA

The International Healthcare Community recommends that countries do not exceed a 15% rate for cesarean section (CS). Our objective was to determine the prevalence and factors associated with CS at GPHC from July to September 2022. Methods: A cross-sectional study was carried out and data were collected from 1296 mothers, who met the inclusion criteria, through face-to-face interviews after obtaining prior informed consent. We performed descriptive analyses both for the outcome and independent variables. Bivariate and multiple logistic regression were used to identify factors associated with CS with a p-value Results: The prevalence of CS at GPHC was 28.9% (95%CI: 26.5-31.5). Factors associated factors with CS were mothers aged 20 to 34 years (AOR: 1.56, 95%CI: 1.02 - 2.39, P = 0.039);mothers who received more than three minimum wages (AOR: 1.95, 95%CI: 1.29 - 2.97, P = 0.002) and who attended prenatal care at both public and private health facilities (AOR: 2.49, 95% CI: 1.19 - 5.22, P = 0.022). Likewise, the highest Odds of CS were observed in mothers with gestational hypertension (AOR: 2.00, 95%CI: 1.35 - 2.96, P Conclusion: The prevalence of CS is higher than the ideal rate recommended by the International Healthcare Community. More studies are needed to understand the reasons for such high prevalence at GPHC.

关键词： Cesarean Section Delivery Georgetown Public Hospital Corporation guyana

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Restoration of Forested Lands under Bauxite Mining with Emphasis on guyana during the First Two Decades of the XXI Century: A Review

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Journal of Geoscience and Environment Protection 2020年第11期8卷 41-67页

作者： Susy Lewis Judith Rosales University of guyana Faculty of Agriculture and Forestry Georgetown Guyana

Mining poses a major environmental threat to tropical forest ecosystems, given its role in long-term forest degradation. Like Suriname, guyana presents one of the less disturbed forested lands in South America. The local economy is improving, thanks to the development of mining which is primarily focused on gold, diamond, and bauxite. This, however, has resulted in long-term degradation of important forest ecosystems and the pollution of water bodies, and these have given rise to increasing concentrations of sediments. Taking into consideration the afore-mentioned, this review synthesizes, for the first time, literature which describes knowledge-based restoration practices in forested fragmented landscapes at different bauxite mining areas. The principal objective of this endeavor is to learn from case studies that have been carried out in the Neotropics especially in South America, with a view to applying best practices to the guyana context. It has been found that mining presents a serious challenge for physical, chemical, and biological restoration. Comprehensive knowledge of the ecology of the landscape—structure and configuration, soil type, physical, chemical and biological properties, dispersal mode, and the identification and quantification/inventory of plant communities is critically important pinpointed for planning restoration programmes. The process of recovering some of the ecological functions of the pristine forest, through natural regeneration, is vital to supporting biodiversity in overburden dumps and to mitigating environmental impacts. One of these many functions, functional connectivity, can be enhanced to optimize the restoration of forest cover leading to an increase in local biodiversity. Bearing in mind the afore-stated, this review synthesizes passive and active restoration through reforestation with local and exotic species, ecological management of colonization, nucleation practices, and the use of Landscape Ecology models. These have bee

关键词： Bauxite Mining Connectivity Forest Degradation guyana Reclamation Restoration

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Review of mammalogical research in the Guianas of northern South America

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Integrative Zoology 2016年第2期11卷 151-161页

作者： Burton K.LIM Royal Ontario Museum TorontoOntarioCanada

Research on mammals in the Guianas of northern South America has had a checkered *** this review,I summarize the notable contributions to mammalogical study in guyana,Suriname and French *** studies began in the mid-18th century with the binomial nomenclature system of scientific classification created by the Swedish naturalist Carl Linnaeus,who described 23 species new to science based on holotype specimens from the *** popular accounts by amateur naturalists visiting this region,over the next 7 decades there was only sporadic taxonomic work done on Guianan mammals primarily by researchers at European *** first comprehensive biological exploration took place in the 1840s during a geographic survey of the boundaries of British ***,it was not until almost half a century later that scientific publications began to regularly document the increasing species diversity in the region,including the prodigious work of Oldfield Thomas at the British Museum of Natural History in *** lull in the study of mammals occurred in the mid-1910s to the early 1960s after which foreign researchers began to rediscover the Guianas and their pristine *** biological renaissance is still ongoing and I give a prospectus on the direction of future research in one of the last frontiers of tropical *** initiative that would be greatly beneficial is the establishment of a university network in the Guianas with graduate-based research to develop a cadre of professional experts on biodiversity and evolution as seen in other countries of South America.

关键词： French Guiana guyana history Mammalia Suriname

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The Environmental Risks Posed by the Oil and Gas Development and Its Potential Impacts on Mangrove Ecosystems and the Coastal Community’s Well-Being

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Journal of Geoscience and Environment Protection 2023年第5期11卷 17-46页

作者： Collin Augustus Henry Thomas B. Singh Temitope D. Timothy Oyedotun Faculty of Earth and Environmental Sciences University of Guyana Turkeyen Campus Greater Georgetown Guyana University of guyana GREEN Institute and Department of Economics University of Guyana Turkeyen Campus Greater Georgetown Guyana Department of Geography Faculty of Earth and Environmental Sciences University of Guyana Turkeyen Campus Greater Georgetown Guyana

guyana is an oil-producing country with oil and gas exploration and production operations approximately 190 km offshore. The coastal communities selected as the study areas in Region 1 and Region 2 are adjacent to the coast and 5 to 10 km inshore. In the event of oil spills, Shell Beach Protected Areas and the other selected communities will be negatively impacted, particularly the mangrove ecosystems and the community’s well-being. The research aims to investigate the potential environmental risks posed by oil and gas exploration and production activities. It followed a qualitative approach and employed semi-structured interviews with the Toshaos of the coastal communities. The data analysis strategy was thematic analysis using the Nvivo software. The major themes included community assets, the importance of mangrove ecosystems, and the impacts of mangrove ecosystem damage through oil spills. Oil spill pollution will negatively impact mangrove ecosystems and the coastal community well-being in Region 1 and Region 2. The major results include damage to cultural artefacts, saltwater intrusion of major creeks, reduced fish catch levels, and agriculture products, which are the main economic activities in the selected communities. Consuming contaminated agriculture and marine products will lead to adverse health problems. Mangrove ecosystems provide considerable benefits to coastal community residents, including shields against river bank erosion, natural habitats for wildlife and source of income, shared traditions, social values, recreational facilities, and tourist attractions. These benefits contribute to the overall coastal community’s well-being. The mangrove forests must be protected and conserved to avoid environmental damage.

关键词： Biodiversity Carbon Credit guyana Health Oil Spill

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