多氯联苯(Aroclor 1242)胁迫下鲤鱼肝脏组织氧化应激   总被引：1，自引：0，他引：1  

王仁君  王建国  丁宁  孙萌  高配科 《海洋与湖沼》2018,49(6):1286-1293

本文在实验室条件下通过静态水质染毒方式在生理生化和转录水平上探究了我国重要经济鱼种鲤鱼(Cyprinus carpioio)对多氯联苯Aroclor 1242的氧化应激:鲤鱼肝脏组织抗氧化酶[超氧化物歧化酶(SuperoxideDismutase,SOD)和过氧化氢酶(Catalase,CAT)]活性、脂质过氧化产物丙二醛(Malonydialdehyde,MDA)含量、相关抗氧化酶编码基因(Cu/Zn-SOD、Mn-SOD、CAT)、应激蛋白HSP70、转录因子Nrf2和芳烃受体AhR2基因表达。结果表明:Aroclor 1242胁迫下,鲤鱼肝脏组织抗氧化酶活性表现出低浓度促进高浓度抑制的趋势;肝脏组织丙二醛含量显著升高,其中390μg/L暴露组鲤鱼肝脏组织MDA含量在第6d高于对照组92.1%(P0.01),表明肝脏组织发生脂质过氧化,膜系统受到损伤;鲤鱼肝脏组织中Cu/Zn-SOD、Mn-SOD、CAT、HSP70、Nrf2和AhR2编码基因表达出现不同程度下调。本文从酶学和基因转录水平上揭示了Aroclor1242胁迫下鲤鱼肝脏组织细胞的氧化应激。  相似文献   

海上设施自动化系统软件认可流程与技术要求研究          下载免费PDF全文

张本伟  李文华 《海洋开发与管理》2018,35(3):62-66

随着计算机及通信技术的发展,海上设施自动化水平的不断提高,海上设施运营的安全可靠性越来越依赖于自动控制系统,尤其是软件部分。由于软件本身在设计和开发中可能存在的缺陷引起系统故障或失效,将给设施及利益方带来不可估量的损失。文章结合IEC61508系列标准、ISO9000—3标准,针对自动化系统软件有关要求和国际船级社协会及船级社等机构有关规范和标准的内容进行分析研究,系统地分析总结出海上设施软件的认可流程及对应技术要求,为我国海工装备设计制造业提供指导。  相似文献   

Galileo广播星历评估及其对定位精度的影响     

韩德强  党亚民  庞辉  薛树强  杨强  张龙平 《大地测量与地球动力学》2018,38(11):1165-1169

分析现阶段伽利略空间信号的精度，并评估伽利略广播星历及其对单点定位的影响。统计30 d健康卫星广播星历，结果表明，FOC和IOV两种类型的广播星历卫星轨道误差优于0.8 m，并且径向误差最小，法向误差次之，切向误差最大；伽利略卫星的钟差误差精度达到1.0 ns；从空间信号测距误差对伽利略卫星进行整体分析，广播星历精度优于1.0 m，FOC与IOV卫星精度相当；用广播星历进行事后单点定位的精度可以达到dm级。  相似文献   

Suspended sediment and total dissolved solid yield patterns at the headwaters of Urumqi River,northwestern China: a comparison between glacial and non‐glacial catchments          下载免费PDF全文

Wenhua Gao  Shu Gao  Zhongqin Li  X. X. Lu  Mingjun Zhang  Shengjie Wang 《水文研究》2014,28(19):5034-5047

In order to understand the differences in the suspended sediment and total dissolved solid (TDS) yield patterns between the glacial and non‐glacial catchments at the headwaters of Urumqi River, northwestern China, water samples were collected from a glacier catchment and an empty cirque catchment within the region, during three melting seasons from 2006 to 2008. These samples were analyzed to estimate suspended sediment and TDS concentrations, fluxes and erosion rates in the two adjoining catchments. There were remarked differences in suspended sediment and TDS yield patterns between the two catchments. Suspended sediment concentrations were controlled mainly by the sediment source, whereas TDS concentrations were primarily related to the hydrologic interaction with soil minerals. Generally, the glacial catchment had much higher suspended sediment and TDS yields, together with higher denudation rates, than the non‐glacial catchment. Overall, glacial catchment was mainly dominated by physical denudation process, whereas the non‐glacial catchment was jointly influenced by physical and chemical denudation processes. The observed differences in material delivery patterns were mainly controlled by the runoff source and the glacial processes. The melting periods of glacier and snow were typically the most important time for the suspended sediment and TDS yields. Meanwhile, episodic precipitation events could generate disproportionately large yields. Subglacial hydrology dynamics, glaciers pluck and grind processes could affect erodibility, and the large quantities of dust stored on the glacier surface provided additional sources for suspended sediment transport in the glacial catchment. These mechanisms imply that, in response to climate change, the catchment behaviour will be modified significantly in this region, in terms of material flux. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Early Jurassic palaeoenvironments in the Surat Basin,Australia – marine incursion into eastern Gondwana     

Andrew D. La Croix  Jianhua He  Valeria Bianchi  Jiahao Wang  Sebastian Gonzalez  Jim R. Undershultz 《Sedimentology》2020,67(1):457-485

Interpretations of palaeodepositional environments are important for reconstructing Earth history. Only a few maps showing the Jurassic depositional environments in eastern Australia currently exist. Consequently, a detailed understanding of the setting of Australia in Gondwana is lacking. Core, wireline logs, two-dimensional and three-dimensional seismic from the Precipice Sandstone and Evergreen Formation in the Surat Basin have been used to construct maps showing the evolution of depositional environments through the Early Jurassic. The results indicate the succession consists of three third-order sequences (Sequence 1 to Sequence 3) that were controlled by eustatic sea level. The lowstand systems tract in Sequence 1 comprises braidplain deposits, confined to a fairway that parallels the basin centre. The strata were initially deposited in two sub-basins, with rivers flowing in different orientations in each sub-basin. The transgressive systems tract of Sequence 1 to lowstand systems tract of Sequence 3 is dominated by fluvio–deltaic systems infilling a single merged basin centre. Finally, the transgressive and highstand systems tracts of Sequence 3 show nearshore environments depositing sediment into a shallow marine basin. In the youngest part of this interval, ironstone shoals are the most conspicuous facies, the thickness and number of which increase towards the north and east. This study interprets a corridor to the open ocean through the Clarence–Moreton Basin, or the Carpentaria and Papuan basins, evidence of which has been eroded. These results challenge a commonly held view that eastern Australia was not influenced by eustasy, and propose a more dynamic palaeogeographic setting comprising a mixture of fluvial, deltaic and shallow marine sedimentary environments. This work can be used to unravel the stratigraphic relationships between Mesozoic eastern Australian basins, or in other basins globally as an analogue for understanding the complex interplay of paralic depositional systems in data poor areas.  相似文献   

Geological mapping reveals the role of Early Jurassic rift architecture in the dispersal of calciturbidites: New insights from the Central and Northern Apennines     

Angelo Cipriani  Martina Caratelli  Massimo Santantonio 《Basin Research》2020,32(6):1485-1509

  相似文献   

How forest gaps shaped plant diversity along an elevational gradient in Wolong National Nature Reserve?     

Chen  Li  Han  Wangya  Liu  Dan  Liu  Guohua 《地理学报(英文版)》2019,29(7):1081-1097

Journal of Geographical Sciences - Understanding the underlying ecological processes that control plant diversity within (α-diversity) and among (β-diversity) forest gaps is important for...  相似文献   

Tectono-sedimentary evolution of Jurassic–Cretaceous diapiric structures: Miravete anticline,Maestrat Basin,Spain     

Jaume Vergés  Yohann Poprawski  Ylènia Almar  Peter A. Drzewiecki  Mar Moragas  Telm Bover-Arnal  Chiara Macchiavelli  Wayne Wright  Grégoire Messager  Jean-Christophe Embry  David Hunt 《Basin Research》2020,32(6):1653-1684

Integration of extensive fieldwork, remote sensing mapping and 3D models from high-quality drone photographs relates tectonics and sedimentation to define the Jurassic–early Albian diapiric evolution of the N–S Miravete anticline, the NW-SE Castel de Cabra anticline and the NW-SE Cañada Vellida ridge in the Maestrat Basin (Iberian Ranges, Spain). The pre shortening diapiric structures are defined by well-exposed and unambiguous halokinetic geometries such as hooks and flaps, salt walls and collapse normal faults. These were developed on Triassic salt-bearing deposits, previously misinterpreted because they were hidden and overprinted by the Alpine shortening. The Miravete anticline grew during the Jurassic and Early Cretaceous and was rejuvenated during Cenozoic shortening. Its evolution is separated into four halokinetic stages, including the latest Alpine compression. Regionally, the well-exposed Castel de Cabra salt anticline and Cañada Vellida salt wall confirm the widespread Jurassic and Early Cretaceous diapiric evolution of the Maestrat Basin. The NE flank of the Cañada Vellida salt wall is characterized by hook patterns and by a 500-m-long thin Upper Jurassic carbonates defining an upturned flap, inferred as the roof of the salt wall before NE-directed salt extrusion. A regional E-W cross section through the Ababuj, Miravete and Cañada-Benatanduz anticlines shows typical geometries of salt-related rift basins, partly decoupled from basement faults. These structures could form a broader diapiric region still to be investigated. In this section, the Camarillas and Fortanete minibasins displayed well-developed bowl geometries at the onset of shortening. The most active period of diapiric growth in the Maestrat Basin occurred during the Early Cretaceous, which is also recorded in the Eastern Betics, Asturias and Basque-Cantabrian basins. This period coincides with the peak of eastward drift of the Iberian microplate, with speeds of 20 mm/year. The transtensional regime is interpreted to have played a role in diapiric development.  相似文献   

Effects of Enclosure on Plant and Soil Nutrients in Different Types of Alpine Grassland     

WANG Fang  HE Yongtao  FU Gang  NIU Ben  ZHANG Haorui  LI Meng  WANG Zhipeng  WANG Xiangtao  ZHANG Xianzhou 《资源与生态学报(英文版)》2020,11(3):290-297

Enclosure is one of the most widely used management tools for degraded alpine grassland on the northern Tibetan Plateau, but the responses of different types of grassland to enclosure may vary, and research on these responses can provide a scientific basis for improving ecological conservation. This study took one site for each of three grassland types (alpine meadow, alpine steppe and alpine desert) on the northern Tibetan Plateau as examples, and explored the effects of enclosure on plant and soil nutrients by comparing differences in plant community biomass, leaf-soil nutrient content and their stoichiometry between samples from inside and outside the fence. The results showed that enclosure can significantly increase all aboveground biomass in these three grassland types, but it only increased the 10-20 cm underground biomass in the alpine desert. Enclosure also significantly increased the leaf nutrient content of the dominant plants and contents of total nitrogen (N), total potassium (K), and organic carbon (C) in 10-20 cm soil in alpine desert, thus changing the stoichiometry between C, N and P (phosphorus). However, enclosure significantly increased only the N content of dominant plant leaves in alpine steppe, while other nutrients and stoichiometries of both plant leaves and soil did not show significant differences in alpine meadow and alpine steppe. These results suggested that enclosure has differential effects on these three types of alpine grasslands on the northern Tibetan Plateau, and the alpine desert showed the most active ecological conservation in the responses of its soil and plant nutrients.  相似文献   

MEEMD-Elman神经网络的电离层TEC预报模型     

汤俊  高鑫 《大地测量与地球动力学》2020,40(4):395-399

利用IGS中心提供的不同纬度的电离层TEC值,建立基于改进的集总平均经验模态分解(MEEMD)算法和Elman回归神经网络(ERNN)模型相结合的电离层TEC预报模型。实验结果表明,在低、中、高不同纬度采用本文方法预报5 d电离层TEC的预测值的均方根误差最优可达到0.96 TECu,相对精度最优达到95.4%,精度较EMD-ERNN模型及单一ERNN模型有显著提高。  相似文献