Complete nuclear ribosomal DNA sequence analyses of the black-footed abalone Haliotis iris     

Zhansheng Guo  Leng Han 《新西兰海洋与淡水研究杂志》2018,52(2):232-246

The black-footed abalone Haliotis iris is an economically important shellfish species in New Zealand. We successfully amplified, sequenced and analysed the complete nuclear ribosomal DNA (nrDNA) of H. iris. The length of the nrDNA was determined to be around 9.6?kb and included, in order, small subunit ribosomal RNA (nrSSU, 1858bp), internal transcribed spacer (ITS, 749?bp), large subunit ribosomal RNA (nrLSU, 3412bp) and an intergenic spacer (IGS, 3560–3662?bp). The nrLSU genes were identical in two individuals, whereas the nrSSU and ITS regions existed at three and four base differences, respectively. The IGS was more variable than the other nrDNA regions. A phylogenetic tree was constructed based on the ITS sequence datasets, which revealed that Haliotidae has two major subclades, mainly distributed in the North Pacific, Europe and Australia. The complete nrDNA sequence will be useful for the classification, phylogeny and breeding of this shellfish.  相似文献   

An algorithm to resolve γ-rays from charged cosmic rays with DAMPE     

Zun-Lei Xu  Kai-Kai Duan  Zhao-Qiang Shen  Shi-Jun Lei  Tie-Kuang Dong  Fabio Gargano  Simone Garrappa  Dong-Ya Guo  Wei Jiang  Xiang Li  Yun-Feng Liang  Mario Nicola Mazziotta  Maria Fernanda Munoz Salinas  Meng Su  Valerio Vagelli  Qiang Yuan  Chuan Yue  Jing-Jing Zang  Ya-Peng Zhang  Yun-Long Zhang  Stephan Zimmer 《天文和天体物理学研究(英文版)》2018,(3)

The DArk Matter Particle Explorer(DAMPE),also known as Wukong in China,which was launched on 2015 December 17,is a new high energy cosmic ray and γ-ray satellite-borne observatory.One of the main scientific goals of DAMPE is to observe Ge V-Te V high energy γ-rays with accurate energy,angular and time resolution,to indirectly search for dark matter particles and for the study of high energy astrophysics. Due to the comparatively higher fluxes of charged cosmic rays with respect to γ-rays,it is challenging to identify γ-rays with sufficiently high efficiency,minimizing the amount of charged cosmic ray contamination. In this work we present a method to identify γ-rays in DAMPE data based on Monte Carlo simulations,using the powerful electromagnetic/hadronic shower discrimination provided by the calorimeter and the veto detection of charged particles provided by the plastic scintillation detector. Monte Carlo simulations show that after this selection the number of electrons and protons that contaminate the selected γ-ray events at～10 Ge V amounts to less than 1% of the selected sample.Finally,we use flight data to verify the effectiveness of the method by highlighting known γ-ray sources in the sky and by reconstructing preliminary light curves of the Geminga pulsar.  相似文献   

OceanRoute: Vessel Mobility Data Processing and Analyzing Model Based on MapReduce     

Chao Liu  Yingjian Liu  Zhongwen Guo  Wei Jing 《中国海洋大学学报(英文版)》2018,17(3):594-602

The network coverage is a big problem in ocean communication, and there is no low-cost solution in the short term. Based on the knowledge of Mobile Delay Tolerant Network (MDTN), the mobility of vessels can create the chances of end-to-end communication. The mobility pattern of vessel is one of the key metrics on ocean MDTN network. Because of the high cost, few experiments have focused on research of vessel mobility pattern for the moment. In this paper, we study the traces of more than 4000 fishing and freight vessels. Firstly, to solve the data noise and sparsity problem, we design two algorithms to filter the noise and complement the missing data based on the vessel’s turning feature. Secondly, after studying the traces of vessels, we observe that the vessel’s traces are confined by invisible boundary. Thirdly, through defining the distance between traces, we design MR-Similarity algorithm to find the mobility pattern of vessels. Finally, we realize our algorithm on cluster and evaluate the performance and accuracy. Our results can provide the guidelines on design of data routing protocols on ocean MDTN.  相似文献   

浙江朱家尖岛东沙海滩对热带风暴“娜基莉”的响应及风暴后的恢复   总被引：1，自引：1，他引：0  

郭俊丽  时连强  童宵岭  郑禹君  徐岱璐 《海洋学报》2018,40(9):137-147

海滩对风暴的响应及风暴后海滩的恢复过程一直以来都是国内外海滩研究的热点。本文通过对浙江舟山市朱家尖岛东沙海滩地形地貌的现场调查，对比分析了热带风暴"娜基莉"影响下东沙海滩剖面的蚀积变化，探讨了海滩在热带风暴发生后的恢复情况。结果表明，在"娜基莉"影响期间，因风暴浪为向岸浪，东沙海滩几乎遭受全线侵蚀，12个剖面单宽侵蚀总量为73.46 m3/m，其中海滩直线段较两个遮蔽段侵蚀显著。由于海滩在风暴前进方向的左侧，且"娜基莉"距东沙较远，使得东沙海滩普遍侵蚀但强度较小。东沙海滩在热带风暴后的恢复过程中，不同部位的地貌调整和冲淤变化不同，下岬角遮蔽段基本趋于稳定，直线段和上岬角遮蔽段在恢复过程中因受海滩季节性调整的影响呈现持续侵蚀。  相似文献   

Crustal structure beneath the central Tien Shan from ambient noise tomography     

Xing Gao  Zhi Guo  Wei Wang  Yuming Wu 《地学学报》2014,26(6):469-476

Through analysis of seismic ambient noise recorded by the GHENGIS array, we constructed a high‐resolution 3‐D crustal shear‐wave velocity model for the central Tien Shan. The obtained shear‐wave velocity model provides insight into the detailed crustal structure beneath the Tien Shan. The results obtained at shallow depths are well correlated with known subsurface geological features. Low velocities are found mainly beneath sedimentary basins, whereas high velocities are mainly associated with mountain ranges. At greater depths of ~43–45 km, high velocities were observed beneath the Tarim Basin and Kazakh Shield; these high velocities extend forward in opposite directions and tilt down towards the central Tien Shan to a depth of in excess of 50 km, most likely reflecting lateral variations in crustal thickness beneath the Tien Shan and surrounding platforms.  相似文献   

Using chlorofluorocarbons (CFCs) and tritium (3H) to estimate groundwater age and flow velocity in Hohhot Basin,China          下载免费PDF全文

Jun Liu  Zongyu Chen  Wen Wei  Yilong Zhang  Zhenghong Li  Fuliang Liu  Hualiang Guo 《水文研究》2014,28(3):1372-1382

The concentrations of chlorofluorocarbons (CFC‐11, CFC‐12 and CFC‐113) and tritium (³H) content in groundwater were used to date groundwater age, delineate groundwater flow systems and estimate flow velocity in the Hohhot basin. The estimated young groundwater age is fallen in the bracket of 21 ~ 50 a and indicates the presence of two different age profiles and flow systems in the shallow groundwater system. Older age waters occur under the topographically low areas, where the aquifer is double‐layer aquifer system consisting of shallow unconfined‐semi‐confined aquifer and deep confined aquifer. This reflects long flow paths associated with regional flow. Groundwater (range from 21 to 34 years) in the north piedmont and east hilly areas, where the aquifer is a single‐layer aquifer consisting of alluvial fans, are typically younger than those in the low areas. The combination of CFCs dating with hydrogeological information indicates that both local and regional flow systems are present at the basin. The regional groundwater flow mainly flows from the north and east to the southwest, the local groundwater flow system occurs nearby the Hohhot city. The mean regional groundwater flow velocity of the shallow groundwater is estimated about 0.73 km/a. These findings can aid in refining hydrogeological conceptual model of the study area. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Piecewise prediction model for watershed‐scale erosion and sediment yield of individual rainfall events on the Loess Plateau,China          下载免费PDF全文

Yu Guo‐Qiang  Zhang Mao‐Sheng  Li Zhan‐Bin  Li Peng  Zhang Xia  Cheng Sheng‐Dong 《水文研究》2014,28(21):5322-5336

Establishing a universal watershed‐scale erosion and sediment yield prediction model represents a frontier field in erosion and soil/water conservation. The research presented here was conducted on the Chabagou watershed, which is located in the first sub‐region of the hill‐gully area of the Loess Plateau, China. A back‐propagation artificial neural model for watershed‐scale erosion and sediment yield was established, with the accuracy of the model, then compared with that of multiple linear regression. The sensitivity degree of various factors to erosion and sediment yield was quantitatively analysed using the default factor test. On the basis of the sensitive factors and the fractal information dimension, the piecewise prediction model for erosion and sediment yield of individual rainfall events was established and further verified. The results revealed the back‐propagation artificial neural network model to perform better than the multiple linear regression model in terms of predicting the erosion modulus, with the former able to effectively characterize dynamic changes in sediment yield under comprehensive factor conditions. The sensitivity of runoff erosion power and runoff depth to the erosion and sediment yield associated with individual rainfall events was found to be related to the complexity of surface topography. The characteristics of such a hydrological response are thus closely related to topography. When the fractal information dimension is greater than the topographic threshold, the accuracy of prediction using runoff erosion power is higher than that of using runoff depth. In contrast, when the fractal information dimension is smaller than the topographic threshold, the accuracy of prediction using runoff depth is higher than that of using runoff erosion power. The developed piecewise prediction model for watershed‐scale erosion and sediment yield of individual rainfall events, which introduces runoff erosion power and runoff depth using the fractal information dimension as a boundary, can be considered feasible and reliable and has a high prediction accuracy. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Concurrent Determination of U‐Pb Age and REE Mass Fractions of Zircon by High Mass Resolution SIMS     

Yu Liu  Qiu‐Li Li  Guo‐Qiang Tang  Xian‐Hua Li 《Geostandards and Geoanalytical Research》2020,44(3):421-437

A combined geochronological and geochemical investigation for the same domain of zircon provides valuable information on timing and genesis, particularly in the case of multi‐growth metamorphic zircon. A high spatial resolution concurrent analytical method for zircon U‐Pb age and rare earth element content was successfully achieved in this study, using a multi‐collector secondary ion mass spectrometer (SIMS) at a ~ 8 μm diameter scale. Special instrument parameters were employed, including a high mass resolution of approximately 15000 applied to replace the previous energy filter method, and a dynamic multi‐collector mode used to reduce the measurement time to 18 min per analysis. Six zircon reference materials yielded precise and accurate ²⁰⁶Pb/²³⁸U ages, which are comparable to those obtained by the ordinary mono‐collector method, but with 2–3 times higher spatial resolution. All zircon grains measured in this study showed enriched heavy‐REE (HREE) contents consistent with previously reported values determined by LA and solution ICP‐MS methods. The light‐REE (LREE) mass fractions measured using both SIMS and LA‐ICP‐MS methods in this study, although with quite different volume, show consistent results within uncertainties.  相似文献   

塔里木盆地苏盖特布拉克剖面寒武系第二统第三阶微生物岩结构类型^*          下载免费PDF全文

李莹  潘文庆  吴亚生  杨果  孙崇浩  姜红霞 《古地理学报》2020,22(4):663-679

塔里木盆地阿克苏地区寒武系第二统第三阶肖尔布拉克组主要由微生物白云岩组成,代表性的剖面在阿克苏市西南90 km处的苏盖特布拉克。由于成岩作用改造严重,对这套微生物碳酸盐岩的特征和形成环境的认识还存在很多分歧,制约了勘探工作。通过详细野外勘察和室内研究,将肖尔布拉克组微生物岩分为4种结构类型: 凝块结构、纹层结构、砂屑结构和骨架结构。首次对凝块结构和纹层结构进行了亚类型的划分,其中凝块结构可划分为蠕虫状、网状和斑点状3种亚类型,纹层结构可划分为致密纹层、短薄纹层、颗粒纹层以及单纹层、纹层组、复合纹层。肖Ⅰ段—肖Ⅲ段发育凝块石白云岩、凝块—层纹石白云岩和层纹石白云岩,肖Ⅳ段发育凝块石微生物丘,肖V段下部发育网状结构凝块石白云岩,肖V段上部发育砂屑白云岩和肾形菌骨架岩。白云石化作用、溶蚀作用、重结晶作用是改变肖尔布拉克组微生物岩结构最重要的成岩作用,且该组下部比上部遭受了更强的成岩作用改造;微生物岩结构对成岩作用改造的抵抗能力为: 砂屑结构>纹层结构>凝块结构。根据微生物岩结构,推测肖Ⅰ段—肖Ⅲ段形成于潮坪环境,肖Ⅳ段和肖V段下部形成于深水潮下环境,肖V段上部形成于浅水潮下环境。以上成果为认识塔里木盆地肖尔布拉克组微生物岩的平面分布规律和今后开展被成岩作用强烈改造的白云岩型微生物岩的研究提供了一个重要参考。  相似文献   

The sulfurization recorded in tridymite in the monomict eucrite Northwest Africa 11591     

Li‐Lin Huang  Bing‐Kui Miao  Guo‐Zhu Chen  Hui‐Min Shao  Zi‐Yuan Ouyang 《Meteoritics & planetary science》2020,55(7):1441-1457

Some of the tridymite in the monomict Northwest Africa (NWA) 11591 eucrite are found to have sulfide‐rich replacement textures (SRTs) to varying degrees. The SRTs of tridymite in NWA 11591 are characterized by the distribution of loose porous regions with aggregates of quartz and minor troilite grains along the rims and fractures of the tridymite, and we propose a new mechanism for the origin of this texture. According to the volume and density conversion relationship, the quartz in the SRT of tridymite with a hackle fracture pattern was transformed from tridymite. We suggest that the primary tridymite grains are affected by the S‐rich vapors along the rims and fractures, leading to the transformation of tridymite into quartz. In addition, the S‐rich vapors reacted with Fe²⁺, which was transported from the relict tridymite and/or the adjacent Fe‐rich minerals, and/or the S‐rich vapors react with the exotic metallic Fe to form troilite grains. The sulfurization in NWA 11591 most likely occurred during the prolonged subsolidus thermal metamorphism in the shallow crust of Vesta and might be an open, relatively high temperature (>800 °C) process. Sulfur would be an important component of the metasomatic fluid on Vesta.  相似文献