检索结果-南通市图书馆

The Global Boundary stratotype Section and Point （GSSP） for the base of the Hirnantian stage （the uppermost of the Ordovician System）

引用

Episodes 2006年第3期29卷 183-196页

作者： Xu Chen Jiayu Rong Junxuan Fan Renbin Zhan Charles E. Mitchell David A. T. Harper Michael J. Melchin Ping＇an Peng stan C. Finney Xiaofeng Wang state Key Laboratory of Palaeobiology and stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences 39 East Beijing Road Nanjing 210008 China department of Geology the State University of New York at Buffalo NY 14260-3050 USA. Geological Museum University of Copenhagen Фster Voldgade 5-7 DK-1350 Copenhagen Denmark department of earth sciences St. Francis Xavier University Antigonish N.S. B2G 2W5 Canada state Key Laboratory of Organic Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China department of Geological sciences California State University at Long Beach Long Beach CA 90840 USA. Yichang Institute of Geology and Mineral Resources 21 Gangyao Road Yichang 443003 China.

The Global boundary stratotype Section and Point (GSSP) for the base of the Hirnantian stage (the uppermost of the Ordovician System) is defined at a point 0.39m below the base of the Kuanyinchiao Bed in the Wangjiawan North section. The section is located near Wangjiawan village, 42 km north of Yichang city (western Hubei, China), at 30° 58′56″N and 111° 25′10″E. The GSSP level coincides with the first appearance of the graptolite species Normalograptus extraordinarius (Sobolevskaya). Secondary markers include the onset of a positive carbon-isotope excursion, and a slightly earlier first appearance of Normalograptus ojsuensis (Koren and Mikhailova). The Wangjiawan North section possesses continuity of sedimentation and biozonation with completeness of exposures, abundant and well-preserved graptolites and shelly fossils, i. e. the Hirnantia-Dalmanitina shelly fauna which is a key element for recognition of the Hirnantian stage. The Wangjiawan North, South and Riverside sections possess favorable facies and widespread correlation potential, are free from structure complication, metamorphism and other alteration, and have good accessibility. The Riverside section in particular possesses amenability to isotopic age determination. The beginning of the Hirnantian was followed by a global episode of a major extinction event, which happened in the Diceratograptus minus Subzone. The proposal was voted by the International Subcommission on Ordovician stratigraphy in October, 2004, approved by the International Commission on stratigraphy in February, 2006, and ratified by the International Union of Geological sciences in May, 2006.

关键词：全球界线层型剖面和节点奥陶纪 GSSP 地层学

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Historical trends of degradation,loss,and recovery in the tropical forest reserves of Ghana

引用

International Journal of Digital earth 2022年第1期15卷 30-51页

作者： Michael C.Wimberly francis K.Dwomoh Izaya Numata Foster Mensah Jacob Amoako Dawn M.Nekorchuk Andrea McMahon department of Geography and Environmental Sustainability University of OklahomaNormanOKUSA department of Geography and Geospatial sciences South Dakota State UniversityBrookingsSDUSA Centre for Remote Sensing and Geographic Information Services University of GhanaAccraGhana The Forestry Commission of Ghana AccraGhana

The Upper Guinean Forest region of West Africa,a globally significant biodiversity hotspot,is among the driest and most human-impacted tropical *** used Landsat to study forest degradation,loss,and recovery in the forest reserves of Ghana from 2003 to *** canopy cover maps were generated using random forests and results were temporally segmented using the LandTrendr *** cover was predicted with a predicted-observed r2 of 0.76,mean absolute error of 12.8%,and mean error of 1.3%.Forest degradation,loss,and recovery were identified as transitions between closed(>60%cover),open(15–60%cover)and low tree cover(sturbance than recovery resulting in a gradual decline in closed canopy *** 2016,widespread fires associated with El Niño drought caused forest loss and degradation across more than 12%of the moist semi-deciduous and upland evergreen forest *** workflow was implemented in Google earth Engine,allowing stakeholders to visualize the results and download *** about historical disturbances will help to prioritize locations for future studies and target forest protection and restoration activities aimed at increasing resilience.

关键词： Landsat random forests machine learning time series LandTrendr drought wildfire

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

古生物多样性统计方法及其适用性分析

引用

古生物学报 2012年第4期51卷 445-462页

作者：陈清樊隽轩 Melchin M J 现代古生物学和地层学国家重点实验室中国科学院南京地质古生物研究所南京210008 department of earth sciences St.Francis Xavier University

以化石产出记录为对象,以时间段为单位的编目式物种多样性统计分析是古生物多样性研究的主要内容。由于地层和化石记录本身的不完整性,以及不同地区和时段各门类化石系统古生物学、生物地层学等方面研究程度的差异,使得多样性统计结果... 详细信息

以化石产出记录为对象,以时间段为单位的编目式物种多样性统计分析是古生物多样性研究的主要内容。由于地层和化石记录本身的不完整性,以及不同地区和时段各门类化石系统古生物学、生物地层学等方面研究程度的差异,使得多样性统计结果往往存在一定偏差,同时不合理的数学统计方法的选用也会对多样性演化形式产生进一步的误读。基于单一时间段内,不同化石延限类型对该时段物种多样性的贡献度的不同看法,存在多种不同的多样性统计方法。而针对时间段跨度、短延限分子比例和生物群多样性变化形式的不同情况,每一种统计方法各自具有一定的适用范围,合理的方法选择能够良好模拟真实情况;反之,不恰当的统计方法则会人为引进更多的偏差。提高原始数据精度、合理划分时间单元和采用不同统计方法对比研究,可以有效的减小偏差。

关键词：古生物多样性分类单元多样性宏演化多样性统计方法统计偏差

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Urogenital schistosomiasis and associated determinant factors among senior high school students in the Dutsin-Ma and Safana Local Government Areas of Katsina state, Nigeria

引用

Infectious Diseases of Poverty 2016年第1期5卷 609-621页

作者： Tolulope Ebenezer Atalabi Umar Lawal francis Omowonuola Akinluyi department of Biological sciences Faculty of ScienceFederal UniversityDutsin-MaP.M.B.5001Dutsin-MaKatsina StateNigeria department of Remote Sensing and GIS School of Earth and Mineral SciencesFederal University of TechnologyAkureOndo StateNigeria

Background:Human schistosomiasis is a chronic parasitic disease of poverty caused by the cercariae of digenetic trematodes of the genus *** disease is a major source of morbidity and mortality in 77 low-and middle-income countries in the tropics where 700 million people are at *** a bid to provide relevant epidemiological information to boost control of urogenital schistosomiasis at the state level in Nigeria,we conducted this study with the aim of investigating the disease’s prevalence and intensity,and the determinant factors responsible for its ***:Data on risk factors were obtained from a total of 645 students aged 12─25 years using well-designed *** were collected between 09:45 and 14:00 in universal ***10μl centrifuged sample was examined for the eggs of *** using Motic®(Binocular)Light Microscope(model S-10-P)with a x10 *** infection intensity was recorded as number of eggs per 10 ml of urine *** data were entered into Microsoft Excel 2010 and analyzed using Epi Info™*** among variables were determined using the chi square test and bivariate and multivariate logistic ***:Prevalence of urogenital schistosomiasis was 30.54%among the study population,with a mean infection intensity of 30.27 eggs/10 ml of *** and average intensity were higher in males(28.37%and 32.21 eggs/10 ml of urine respectively)than in females(2.17%and 5 eggs/10 ml of urine respectively).Water contact activities(χ^(2)=29.031,P=0.0000),sex(male)[χ^(2)=109.82;P<0.0001],location(Dutsin─Ma)[χ^(2)=7.19;P=0.0073],age group 18-20(χ^(2)=4.819,P=0.0281),altitude(531─560 m)[χ^(2)=6.84,p=0.0089],fathers doing other brown─collar jobs(χ^(2)=8.449,P=0.0037)and mothers’occupation(χ^(2)=9.470,P=0.0021)were found to be significantly associated with urogenital *** were six times more likely to be infected with the cercariae of *** compared to girls[AOR

关键词： Prevalence Intensity Urogenital schistosomiasis Risk─factors Katsina state Nigeria

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Report of the restudy of the defined global stratotype of the base of the Silurian System

引用

Episodes 2008年第3期31卷 315-318页

作者： Jiayu Rong Michael Melchin S. Henry Williams Tatyana N. Koren Jacques Verniers SKL Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences 210008 Nanjing PRC department of Geology St. Francis Xavier University Antigonish NS B2G 2W5 Canada Petro-Canada Oil and Gas 150 - 6th Avenue SW Calgary AB T2P 3E3 Canada All Russian Geological Research Insfitute-VSEGEI Sredny pr. 74 199026 St. Petersburg Russia Research Unit Palaeontology Ghent University Krijgslaan 281/S 8 2000 Ghent Belgium

The Global stratotype Section and Point (GSSP) for the base of the Silurian System was defined in 1985. Since that time, a number of researchers have suggested that this section has serious deficiencies for use as a GSSP As a result, in 2000, the Subcommission on Silurian stratigraphy (SSS) proposed undertaking a formal restudy of this GSSR, which was subsequently approved by the International Commission of stratigraphy (ICS). The result of this restudy was the formal proposal that the current GSSP, at 1.6 m above the base of the Birkhill Shale, at Dob's Linn, Scotland, should be maintained as the same locality and stratigraphic level, but the biostratigraphical definition of the boundary should be revised. The previously defined, basal Silurian graptolite zone, the Parakidograptus acuminatus Zone, should be subdivided into a lower Akidograptus ascensus Zone and a higher P. acuminatus Zone. The base of the A. ascensus Zone, marked by the first appearance of A. ascensus, should be regarded as the biostratigraphic mark for the base of the Silurian. This proposal has now been formally approved by the SSS and ICS, and ratified by International Union of Geological sciences. This is the first GSSP to undergo formal restudy and redefinition, and the proposal also included a recommended procedure for restudy of GSSPs.

关键词：全球层形志留纪地质学研究项目

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Guest Editorial for Special Issue on Blockchain for Internet-of-Things and Cyber-Physical Systems

引用

IEEE/CAA Journal of Automatica Sinica 2021年第12期8卷 1867-1867页

作者： Mohammad Mehedi Hassan Giancarlo Fortino Laurence T.Yang Hai Jiang Kim-Kwang Raymond Choo Jun Jason Zhang Fei-Yue Wang King Saud university RiyadhSaudi Arabia university of Calabria Italy st.francis xavier university Canada Arkansas state university USA department of Information Systems and Cyber Security University of Texas at San AntonioSan AntonioTX 78249-0631USA Wuhan university WuhanChina Institute of Automation Chinese Academy of SciencesBeijing 100190China

Cyber-physical systems(CPS)are increasingly commonplace,with applications in energy,health,transportation,and many other *** of the major requirements in CPS is that the interaction between cyber-world and man-made physical world(exchanging and sharing of data and information with other physical objects and systems)must be safe,especially in bi-directional *** particular,there is a need to suitably address security and/or privacy concerns in this human-in-the-loop CPS ***,existing centralized architecture models in CPS,and also the more general IoT systems,have a number of associated limitations,in terms of single point of failure,data privacy,security,robustness,*** limitations reinforce the importance of designing reliable,secure and privacy-preserving distributed solutions and other novel approaches,such as those based on blockchain technology due to its features(e.g.,decentralization,transparency and immutability of data).This is the focus of this special issue.

关键词： Internet limitations transparency

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Neoarchean and Rhyacian TTG-Sanukitoid suites in the southern S?o francisco Paleocontinent,Brazil:Evidence for diachronous change towards modern tectonics

引用

Geoscience Frontiers 2020年第5期11卷 1763-1787页

作者： Henrique Bruno Vitalino Elizeu Monica Heilbron Claudio de Morisson Valeriano Rob strachan Mike Fowler Samuel Bersan Hugo Moreira Ivo Dussin Luiz Guilherme do Eirado Silva Miguel Tupinamba Julio Almeida Carla Neto Craig storey Universidade Do Estado Do Rio de Janeiro Faculdade de GeologiaTektosGrupo de Pesquisa Em GeotectonicaRua Sao Francisco Xavier 524MaracanaRio de JaneiroBrazil university of Portsmouth School of Earth and Environmental SciencesBurnaby BuildingBurnaby RoadPortsmouthUK Universit€at Salzburg Department of Geography and GeologyKapitelgasse4-65020SalzburgAustria Universidade Federal de Ouro Preto Departamento de GeologiaCampus Morro Do CruzeiroOuro PretoMGBrazil Laboratorio de Geocronologia e Isotopos Radiog^enicos Universidade Do Estado Do Rio de JaneiroRua Sao Francisco Xavier 524MaracanaRio de JaneiroBrazil

The southern portion of the Sao francisco Palaeocontinent in Brazil is denoted by Archean nuclei and Paleoproterozoic magmatic arcs that were amalgamated during Siderian to Orosirian orogenic processes(ca.2.4-2.1 Ga).New isotopic U-Pb in zircon and Sm-Nd whole rock combined with major and trace element composition analyses constrain the crystallization history of the Neoarchean Piedade block(at ca.2.6 Ga)and the Paleoproterozoic Mantiqueira Complex(ca.2.1-1.9 Ga).These therefore display quite different magmatic histories prior to their amalgamation at ca.2.05 ***-Nd and Rb-Sr isotopes imply a mixed mantle-crustal origin for the samples in both units.A complete Palaeoproterozoic orogenic cycle,from subduction to collision and collapse,is recorded in the Piedade Block and the Mantiqueira *** to Orosirian subduction processes(ca.2.2-2.1 Ga)led to the generation of coeval(ca.2.16 Ga)TTG suites and sanukitoids,followed by late(2.10-2.02 Ga)high-K granitoids that mark the collisional *** collisional accretion of the Mantiqueira Complex against the Piedade Block at 2.08-2.04 Ga is also recorded by granulite facies metamorphism in the latter terrane,along the Ponte Nova suture *** collisional stage was closely followed by the emplacement of within-plate tholeiites at ca.2.04 Ga and by alkaline rocks(syenites and enriched basic rocks)at ca.1.98 Ga,marking the transition to an extensional tectonic *** discovery of two episodes of TTG and sanukitoid magmatism,one during the Neoarchean in the Piedade Complex and another during the Rhyacian in the Mantiqueira Complex,indicates that the onset of subduction-related melting of metasomatized mantle was not restricted to Neoarchean times,as generally believed,but persisted much later into the Paleoproterozoic.

关键词： Geodynamics High Ba–Sr granitoids Diachronous TTG-Sanukitoid transition Paleoproterozoic Mantiqueira complex

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

湖北恩施太阳河奥陶纪-志留纪之交沉积间断的研究

引用

地层学杂志 2011年第4期35卷 361-367页

作者：王怿樊隽轩张元动徐洪河 M.J. Melchin 现代古生物学和地层学国家重点实验室中国科学院南京地质古生物研究所江苏南京210008 department of earth sciences St. Francis Xavier University Antigonish NS B2G 2W5 Canada

依据湖北恩施太阳河灯草坪奥陶系—志留系剖面的生物地层学和岩石学的研究,该剖面的沉积间断发生在Paraorthograptus pacificus带至Coronograptus cyphus带之间,共缺失5个笔石带。奥陶系、志留系之间黏土岩矿物分析显示,在奥陶系、志留... 详细信息

依据湖北恩施太阳河灯草坪奥陶系—志留系剖面的生物地层学和岩石学的研究,该剖面的沉积间断发生在Paraorthograptus pacificus带至Coronograptus cyphus带之间,共缺失5个笔石带。奥陶系、志留系之间黏土岩矿物分析显示,在奥陶系、志留系之间出现有高岭土,推断在其间可能上升为陆地。具体演变过程为:在晚奥陶世晚期***带之前,该区属于黑色笔石页岩沉积环境;在***带(也可能略早),该区抬升,形成水下高地,其沉积环境达到了水下风化面,出现了生物扰动现象,并伴有一定的水下动力作用;至奥陶纪最晚期—志留纪早期,该区进一步抬升,可能上升为陆地;至志留纪早期***带,该区快速下降,恢复到黑色笔石页岩沉积环境。凯迪晚期的全球海平面下降和志留纪早期"华夏古陆"不断向西及西北扩展的耦合作用是导致该区上升为陆地的主要因素。对整个扬子地区奥陶纪-志留纪之交沉积间断的综合分析需要在多个剖面开展进一步的研究工作。

关键词：生物地层岩石地层笔石沉积间断奥陶系志留系恩施湖北

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The Case of the Carnian(Triassic) Conodont Genus Metapolygnathus Hayashi

引用

Journal of earth Science 2015年第2期26卷 219-223页

作者： Ali Murat Kili Pablo Plasencia Keisuke Ishida francis Hirsch department of Geological Engineering Balikesir University department of Geology and ICBIBE University of ValenciaDr. Moliner 50. 46100 Burjassot Spain Laboratory of Geology Faculty of Sciences Tokushima University Laboratory of Geology Faculty of Sciences Naruto University

Successive evolutionary trends control the genera Paragondolella Mosher and Meta- polygnathus Hayashi over the about 20 Ma long Aegean-Tuvalian timespan. In consideration of their evolutionary criteria, these genera have been retained together with Carnepigondolella Kozur and the two new genera proposed herein, MazzaeUa （type species M. carnica） and Hayashiella （type species H. nodosa）. Mazzaella n. gen. represents a Late Julian side branch ofMetapolygnathus, harbouring a platform ornamentation similar to the several million years younger Tuvalian lineage of Carnepigondolella, issued from Hayashiella n. gen. that is intermediary between Metapolygnathus and CarnepigondoleUa, based on appearance and platform ornamentation.

关键词： Carnian conodont phylogeny evolutionary trend.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Baossi–Warack monogenetic volcanoes, Adamawa Plateau,Cameroon: petrography, mineralogy and geochemistry

引用

Acta Geochimica 2019年第1期38卷 40-67页

作者： Anicet Feudjio Tiabou Robert Temdjim Pierre Wandji Jacques-Marie Bardintzeff Vivian Bih Che Edith Ekatah Bate Tibang Caroline Neh Ngwa Fran?ois xavier Onana Mebara Remote Sensing Unit Faculty of Science Department of Geology University of Buea department of earth sciences Faculty of Science University of Yaoundé 1 Laboratoire de Géologie Ecole Normale Supérieure de Yaoundé Univ.Paris-Sud Sciences de la Terre VolcanologiePlanétologie UMR CNRS 8148 GEOPS Bat.504 Université Paris-Saclay Higher Teacher Training College Department of GeologyUniversity of Bamenda Institute for Geological and Mining Research (IRGM) Institute for Geological and Mining Research (IRGM) Branch of Volcanologic and Geophysics Research (ARGV)

Three monogenetic cones in the Baossi–Warack area, Ngaoundéré, Adamawa Plateau forming part of the Cameroon Volcanic Line(CVL) are documented in this study. Basaltic lavas(<1 km^3) scattered around these vents and ... 详细信息

Three monogenetic cones in the Baossi–Warack area, Ngaoundéré, Adamawa Plateau forming part of the Cameroon Volcanic Line(CVL) are documented in this study. Basaltic lavas(stricted volcaniclastic deposits were emplaced by Hawaiian and mild strombolian style eruptions. The lavas are porphyritic, mainly composed of olivine(chrysolite) and clinopyroxene(diopside and augite) phenocrysts and plagioclase(andesine) microphenocrysts. Accessory minerals include titano-magnetite and titano-hematite, nepheline,apatite and amphibole xenocrysts. Sanidine occurs in some samples and sodi-potassic albite in others. Some olivines and clinopyroxenes exhibit resorbed margins and thin reaction rims while plagioclase displays oscillatory zoning, and sieved textures as a result of magma mixing. Whole-rock geochemistry data indicates that the lavas are silica-undersaturated, composed of basanites and basalts, showing little compositional variations(SiO_2: 39.20 wt.%–48.01 wt.%,MgO: 5.29 wt.%–9.70 wt.%). Trace elements patterns of these lavas suggest they are enriched in LILE including Pb,probably due to crustal contamination. REE patterns suggest cogenetic magmas below Baossi 1 and Baossi 2 volcanoes,and distinct sources below Warack volcano and nearby *** lavas studied show affinity to high-μ(HIMU), enriched type Ⅰ(EM1) and Oceanic Island Basalt(OIB)-like mantle signatures and thus indicate a heterogeneous mantle source underneath the vents as noted at other monogenetic and polygenetic volcanoes along the CVL. Primary melts derived from low degrees of partial melting(0.5%–2%) and encountered low rates of fractionation, and crustal contamination coupled with magma mixing. These melts evolved independently through structural weaknesses in the basement.

关键词： Cameroon volcanic line Adamawa Plateau Volcanic field Monogenetic volcano Magma mixing Petrogenesis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：