检索结果-南通市图书馆

Geochronological constraints on the metamorphic sole of the Semail ophiolite in the United Arab Emirates

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2016年第4期7卷 609-619页

作者： Nick M.W.Roberts Robert j.Thomas joachim jacobs NERC Isotope Geosciences Laboratory British Geological SurveyKeyworthNG12 5GGUK Council for Geoscience P.O.Box 572Bellville 7535South Africa University of Bergen.Department of Earth Science PB 78035020 BergenNorway Norwegian Polar Institute Fram Centre9296 TromsoNorway

The Semail ophiolite of Oman and the United Arab Emirates （UAE） provides the best preserved large slice of oceanic lithosphere exposed on the continental crust, and offers unique opportunities to study processes of ocean crust formation, subduction initiation and obduction. Metamorphic rocks exposed in the eastern UAE have traditionally been interpreted as a metamorphic sole to the Semail ophiolite. However, there has been some debate over the possibility that the exposures contain components of older Arabian continental crust. To help answer this question, presented here are new zircon and futile U-Pb geochronological data from various units of the metamorphic rocks. Zircon was absent in most samples. Those that yielded zircon and futile provide dominant single age populations that are 95-93 Ma, partially overlapping with the known age of oceanic crust formation （96.5-94.5 Ma）, and partially overlapping with cooling ages of the metamorphic rocks （95 90 Ma）. The data are interpreted as dating high-grade metamorphism during subduction burial of the sediments into hot mantle lithosphere, and rapid cooling during their subsequent exhumation. A few discordant zircon ages, interpreted as late Neoproterozoic and younger, represent minor detrital input from the continent. No evidence is found in favour of the existence of older Arabian continental crust within the metamorphic rocks of the UAE.

关键词： Semail ophiolite United Arab Emirates Metamorphic sole U-Pb geochronology Zircon Rutile

Another look at social innovation:From community-For community

在线全文

学校读者我要写书评

暂无评论

International journal of Innovation Studies 2022年第2期6卷 92-101页

作者： Lisa j.Daniel Peter jenner School of Business and Creative Industries University of the Sunshine CoastFraser CoastQueensland4655Australia

Social innovation(SI)continues to raise interest among scholars and policymakers,as a potential panacea for social disenfranchisement and civic *** is troubling is diverse perspectives of SI abound,creating inconsistencies in methodological approaches which confound theory *** paper clarifies that discussion by considering the locus of initiation and locus of benefit as informing characteristics that differentiate grounded social innovation from other types of well-recognized socially beneficent *** notion of‘from community e for community’is presented to aid understanding of the unique nature of authentically grounded social *** paper is significant as it presents a practical approach to help researchers and practitioners consider where opportunities for targeted policy support,institutional involvement,and agency action can aid community development and wellbeing.

关键词： Social innovation Community markets Social change Community development

Fungal-contaminated grass and well water and sporadic amyotrophic lateral sclerosis

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

Neural Regeneration Research 2019年第9期14卷 1490-1493页

作者： Peter William French Russell Ian Ludowyke Gilles j.Guillemin School of Medicine University of New South WalesSydneyNSWAustralia Willoughby SydneyNSWAustralia Neuroinflammation Group Department of Biological SciencesFaculty of Medicine and Health SciencesMacquarie UniversitySydneyNSWAustralia

Fungi are important infectious disease-causing agents,but are often overlooked as environmental factors in *** review several lines of evidence that point to a potential fungal origin of sporadic amyotrophic lateral sclerosis(ALS),the most common form of motor neurone *** 90%cases of ALS are sporadic,and the aetiology of sporadic ALS is still *** have previously postulated that grass or soil-associated fungal infections may be a leading cause of sporadic *** we extend this proposal to water-associated fungi.A wide variety of fungi have been reported in drinking water including Acremonium,Alternaria,Aspergillus,Cladosporium,Fusarium,Penicillium and *** of these are known to produce neurotoxic *** this,drinking water is not routinely monitored for fungal *** contamination could explain the close correlation between distribution of well water and cases of sporadic ALS in the United *** propose several mechanisms by which an opportunistic fungal infection from environmental exposure(to water,soil or plants)can lead to long term neuronal degradation resulting in the hallmarks of *** confirmed,the association between fungal infection and sporadic ALS could lead to novel treatment strategies for this progressive and fatal disease.

关键词： amyotrophic lateral sclerosis fungi motor neurone disease mycotoxins neurotoxins ALS well water sporadic ALS

Formin' bridges between microtubules and actin filaments in axonal growth cones

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2017年第12期12卷 1971-1973页

作者： István Foldi Szilárd Szikora józsef Mihály Institute of Genetics Biological Research Centre HungarianAcademy of Sciences MTA-SZBK NAP B Axon Growth andRegeneration Group Szeged Hungary

It is well established that guidance of axons during neuronal development is regulated by a variety of extracellular signals,governing cytoskeletal dynamics in growth *** actin and microtubule（MT）cytoskeleton have both been shown to play important ***,a growing body of work suggests that a critical issue is the proper coordination of changes within these two major cytoskeletal systems（reviewed in Cammara-ta et al., 2016）.

关键词： Formin'' bridges axonal growth cones

Microstructural evolution during unsteady-state horizontal solidification of Al-Si-Mg(356) alloy

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2018年第6期28卷 1073-1083页

作者： j.O.LIMA C.R.BARBOSA I.A.B.MAGNO j.M.NASCIMENTO A.S.BARROS M.C.OLIVEIRA F.A.SOUZA O.L.ROCHA Federal Institute of Education Science and Technology of Para IFPA 66093-220 Belem PA Brazil Federal University of Para Institute of Technology UFPA 66075-110 Belem PA Brazil

The increasing demand for reducing vehicle weight in the automotive and aerospace industries has raised the need to develop improved structural aluminum-based alloys. Thus, horizontal solidification experiment with the Al-7%Si-0.3%Mg（mass fraction） alloy was carried out. A water-cooled horizontal directional solidification device was developed and used. Microstructural characterization was carried out using traditional techniques of metallography, optical microscopy and SEM microscopy. The Thermo-Calc software was used to generate the solidification path of the investigated alloy with addition of 0.17% Fe（mass fraction）. The effects of the thermal parameters such as the growth rate（VL）, cooling rate（TC） and solidification local time（tSL） on the formation of the macrostructure and on the dendritic microstructure evolution were evaluated. A columnar to equiaxed transition（CET） was found for VL and TC values from 0.82 to 0.98 mm/s and from 1.71 to 2.55 ℃/s, respectively. The microstructure was characterized by the measurement of the primary and secondary dendrite arm spacings（λ1 and λ2, respectively）. Experimental laws of λ1 =f（VL, TC） and λ2 =f（tSL） were proposed. It is observed that the interdendritic region is composed of the following eutectic mixture： a（Al）＋Si＋p-Al8 Mg3 Fe Si6＋q-Mg2 Si.

关键词： Al-Si-Mg alloy microstructural transition dendrite arm spacing transient heat flow

Homopteran Vector Biomarkers for Efficient Circulative Plant Virus Transmission are Conserved in Multiple Aphid Species and the Whitefly Bemisia tabaci

在线全文

学校读者我要写书评

暂无评论

journal of Integrative Agriculture 2012年第2期11卷 249-262页

作者： Michelle Cilia Michael Bereman Tara Fish Michael j MacCoss stewart Gray USDA-ARS Robert W. Holley Center for Agriculture and Health Tower Road Ithaca New York 14853 USA Department of Plant Pathology and Plant-Microbe Biology Cornell University Ithaca New York 14853 USA Department of Genome Sciences University of Washington Seattle Washington 98195-5065 USA

Plant viruses in the families Luteoviridae and Geminiviridae are phloem restricted and are transmitted in a persistent,circulative manner by homopteran *** fluorescence 2-D difference gel electrophoresis to compare the proteomes of F2 genotypes of Schizaphis graminum segregating for virus transmission ability,we recently discovered a panel of protein biomarkers that predict vector *** we used aphid and whitefly nucleotide and expressed sequence tag database mining to test whether these biomarkers are conserved in other homopteran *** gene homologs that shared a high degree of predicted amino acid identity were discovered in two other aphid species and in the whitefly Bemisia *** reaction monitoring mass spectrometry was used to validate the expression of these biomarkers proteins in multiple aphid vector *** conservation of these proteins in multiple insect taxa that transmit plant viruses along the circulative transmission pathway creates the opportunity to use these biomarkers to rapidly identify insect populations that are the most efficient vectors and allow them to be targeted for control prior to the spread of virus within a crop.

关键词： aphid whitefly Schizaphis graminum Bemisia tabaci Acyrthosiphon pisum Toxoptera citricida Myzuspersicae proteomics biomarker circulative transmission begomovirus luteovirus geminivirus leaflaopper,selected reaction monitoring SRM mass spectrometry targeted proteomics Skyline

FORMATION OF Fe-N COMPOUNDS BY LASER NITRIDATION IN AN ATMOSPHERIC AMBIENT

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2003年第2期16卷 139-144页

作者： Y.L.Yang F.j.Sun D.Zhang College of Science Northeastern UniversityShenyang 110004ChinaCollege of ScienceNortheastern UniversityShenyang 110004ChinaCollege of ScienceNortheastern UniversityShenyang 110004China

The formation of Fe-N compounds by laser nitriding in an atmospheric ambient was reported. By CW-CO2 laser irradiation on pure ferrite iron in the atmospheric ambient, Fe-N compounds (including Fe2N, .Fe3AT and Fe4N) are formed as a result of a laser-enhanced and temperature-enhanced reactions. The samples were analyzed with X-ray diffraction. It is found that the laser power density, scanning speed and nitrogen temperature are the main factors influencing the formation of Fe-N compounds. Nitrogen can be activated by pre-heating at some temperature. Nitrogen activation and sample surface melting by CW-CO2 laser greatly enhance the reaction between the sample surface and nitrogen beam. After annealing at 500℃for 3h, some Fe2N and Fe3N converted into more stable Fe4N.

关键词： laser nitriding nitride Fe-N compound

A decision framework for identifying models to estimate forest ecosystem services gains from restoration

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2016年第2期3卷 126-137页

作者： Zachary L. Christin Kenneth j. Bagstad Michael A. Verdone Earth Economics 107 N Tacoma Ave Tacoma WA 98403 USA. U.S. Geological Survey Geosciences & Environmental Change Science Center Box 25046 MS 980 Denver CO 80225 USA. International Union for the Conservation of Nature 1630 Connecticut Ave. NW #300 Washington DC 20009 USA.

Restoring degraded forests and agricultural lands has become a global conservation priority. A growing number of tools can quantify ecosystem service tradeoffs associated with forest restoration. This evolving ＂tools landscape＂ presents a dilemma： more tools are available, but selecting appropriate tools has become more challenging. We present a Restoration Ecosystem Service Tool Selector （RESTS） framework that describes key characteristics of 13 ecosystem service assessment tools. Analysts enter information about their decision context, services to be analyzed, and desired outputs. Tools are filtered and presented based on five evaluative criteria： scalability, cost, time requirements, handling of uncertainty, and applicability to benefit-cost analysis. RESTS uses a spreadsheet interface but a web-based interface is planned. Given the rapid evolution of ecosystem services science, RESTS provides an adaptable framework to guide forest restoration decision makers toward tools that can help quantify ecosystem services in support of restoration.

关键词： Decision support Ecosystem services Forest restoration Modeling Valuation Comparative toolsassessment

Diversity, regeneration status and population structure of gum-and resin-bearing woody species in south Omo zone, southern Ethiopia

在线全文

学校读者我要写书评

暂无评论

journal of Forestry Research 2014年第2期25卷 319-328页

作者： Muhamed Adem Adefires Worku Mulugeta Lemenih Wubalem Tadesse jürgen Pretzsch Madawalabu University Technical University of Dresden Institute of International Forestry and Forest Products Wondo Genet College of Forestry and Natural Resources Ethiopian Institute of Agricultural Research Forestry Research Sector

South Omo Administrative Zone in Ethiopia is home to 18 indigenous ethnic groups whose livelihood is vulnerable due to recurrent drought and degradation. Despite the preliminary observation showing the rich dry-forest resource base that, if sustainably managed could enhance livelihoods and biodiversity conservation, there is lack of empirical data on its current status. We conducted a study aiming at quantifying the population status of gum- and resin-bearing species in two randomly selected districts, Hamer and Bena-Tsemay. Seventy-five quadrats （35 at Hamer and 40 at Bena-Tsemay） each measuring 400 m2 were established along line transects to assess species diversity and equitability, density, frequency, dominance, importance value and population structure. We recorded a total of 27 woody species of 12 families and 14 genera. Fifteen species （9 at Hamer and 14 at Bena-Tsemay） of the genera Acacia, Boswellia, Commiphora and Sterculia, were identified as either major sources of commercial gums and resins or their adulterants. Gum- and resin-bearing species comprised 56% and 57% of species richness, 48% and 50% of total density per ha, 95% and 98% of basal area, and 64% and 56% of importance values at Hamer and Bena-Tsemay, respectively. Diversity of the entire woody species assemblage and of the gum- and resin-bearing species was slightly higher at Bena-Tsemay （H= 2.61, 1.4） than at Hamer （H＇= 2.48, 1.28）, respectively. The diversity and abundance of the resource base suggest potential for development of value-added commercialization of gum and resins to enhance livelihoods and encourage sustainable management of the forest at these study areas. We recorded, however, declining natural regeneration of most gum- and resin-bearing species, and this calls for integrated and participatory species management and landscape rehabilitation.

关键词： Acacia Boswellia Commiphora Sterculia gum and resins population status southern Ethiopia