斑节对虾GPx3a基因的分子克隆及表达分析

谷胱甘肽过氧化物酶(Glutathione peroxidase,GPx)是生物体内重要的抗氧化酶,能防止过氧化氢对生物体的氧化应激。该研究利用RACE技术获得了斑节对虾(Penaeus monodon)GPx3a(PmGPx3a)的全长c DNA序列,进行了相关生物信息学分析。作者利用荧光定量PCR方法研究了PmGPx3a在斑节对虾不同组织的表达情况。探究了PmGPx3a在不同胁迫条件下(盐度、重金属和细菌)的表达情况。结果表明PmGPx3a c DNA全长1135 bp,其中开放阅读框(ORF)长651 bp,预测编码216个氨基酸。PmGPx3a推导的氨基酸序列与其他动物的GPx3a氨基酸序列具有高度一致性。实时定量PCR结果显示,在高低盐胁迫下,PmGPx3a在肝胰腺中相对表达量都为上升的(p0.05)。在铜、锌、铬胁迫中,鳃中的PmGPx3a的相对表达量总体呈现下降趋势,在肝胰腺中呈现上升趋势。在哈维弧菌(Vibrio harveyi)刺激下,PmGPx3a在血淋巴中的相对表达量总体呈现上升趋势,24 h后表达量最大,显著高于对照组2.2倍(P0.05)。以上研究结果表明,PmGPx3a基因参与了斑节对虾对环境胁迫和氧化应激的适应性反应。     

次火山热变质煤中Ge、Ga、As、S的分布特征

五牧场区是内蒙东部伊敏褐煤盆地中一个因次火山侵入作用形成的局部的烟煤区。在煤变质过程中,锗、硫从高变质煤中逸出,并在上部低变质煤中富集。锗、硫、砷与煤中有机质呈正相关,镓与煤中灰分呈正相关,随变质程度增加相关性下降。      

Multi‐method (14C, 36Cl, 234U/230Th) age bracketing of the Tschirgant rock avalanche (Eastern Alps): implications for absolute dating of catastrophic mass‐wasting

Correct and precise age determination of prehistorical catastrophic rock‐slope failures prerequisites any hypotheses relating this type of mass wasting to past climatic regimes or palaeo‐seismic records. Despite good exposure, easy accessibility and a long tradition of absolute dating, the age of the 230 million m³ carbonate‐lithic Tschirgant rock avalanche event of the Eastern Alps (Austria) still is relatively poorly constrained. We herein review the age of mass‐wasting based on a total of 17 absolute ages produced with three different methods (¹⁴C, ³⁶Cl, ²³⁴U/²³⁰Th). Chlorine‐36 (³⁶Cl) cosmogenic surface exposure dating of five boulders of the rock avalanche deposit indicates a mean event age of 3.06 ± 0.62 ka. Uranium‐234/thorium‐230 (²³⁴U/²³⁰Th) dating of soda‐straw stalactites formed in microcaves beneath boulders indicate mean precipitation ages of three individual soda straws at 3.20 ± 0.26 ka, 3.04 ± 0.10 ka and 2.81 ± 0.15 ka; notwithstanding potential internal errors, these ages provide an ‘older‐than’ (ante quam) proxy for mass‐wasting. Based on radiocarbon ages (nine sites) only, it was previously suggested that the present rock avalanche deposit represents two successive failures (3.75 ± 0.19 ka bp , 3.15 ± 0.19 ka bp ). There is, however, no evidence for two events neither in surface outcrops nor in LiDAR derived imagery and drill logs. The temporal distribution of all absolute ages (¹⁴C, ³⁶Cl, ²³⁴U/²³⁰Th) also does not necessarily indicate two successive events but suggest that a single catastrophic mass‐wasting took place between 3.4 and 2.4 ka bp . Taking into account the maximum age boundary given by reinterpreted radiocarbon datings and the minimum U/Th‐ages of calcite precipitations within the rock avalanche deposits, a most probable event age of 3.01 ± 0.10 ka bp can be proposed. Our results underscore the difficulty to accurately date catastrophic rock slope failures, but also the potential to increase the accuracy of age determination by combining methods. Copyright © 2016 John Wiley & Sons, Ltd.     

Mercury contamination in Southern New England coastal fisheries and dietary habits of recreational anglers and their families: Implications to human health and issuance of consumption advisories

Total mercury (Hg) was measured in coastal fishes from Southern New England (RI, USA), and Hg exposure was estimated for anglers and family members that consumed these resources. Fish Hg was positively related to total length (n = 2028 across 7 fish species), and interspecies differences were evident among legally harvestable fish. Many recreational anglers and their families experienced excessively high Hg exposure rates, which was attributed to the enriched Hg content of frequently consumed fishes. Specifically, 51.5% of participants in this study had Hg exposures exceeding the US EPA reference dose, including 50.0% of women of childbearing years. These results are noteworthy given that Hg neurotoxicity occurs in adults and children from direct and prenatal low-dose exposure. Moreover, this study underscores the need for geographic-specific research that accounts for small-scale spatial variations in fish Hg and dietary habits of at-risk human populations.     

The CREp program and the ICE-D production rate calibration database: A fully parameterizable and updated online tool to compute cosmic-ray exposure ages

Over the last decades, cosmogenic exposure dating has permitted major advances in many fields of Earth surface sciences and particularly in paleoglaciology. Yet, exposure age calculation remains a complicated and dense procedure. It requires numerous choices of parameterization and the use of an accurate production rate.This study describes the CREp program (http://crep.crpg.cnrs-nancy.fr) and the ICE-D production rate online database (http://calibration.ice-d.org). This system is designed so that the CREp calculator will automatically reflect the current state of this global calibration database production rate, ICE-D. ICE-D will be regularly updated in order to incorporate new calibration data and reflect the current state of the available literature.CREp is a Octave/Matlab^© online code that computes Cosmic Ray Exposure (CRE) ages for ³He and ¹⁰Be. A stand-alone version of the CREp code is also released with the present article. Note however that only the online version is connected to the online database ICE-D. The CREp program offers the possibility to calculate ages with two scaling models: i.e. the empirical Lal-Stone time-dependent model (Balco et al., 2008; Lal, 1991; Stone, 2000) with the muon parameters of Braucher et al. (2011), and the Lifton-Sato-Dunai (LSD) theoretical model (Lifton et al., 2014). The default atmosphere model is the ERA-40 database (Uppala et al., 2005), but one may also use the standard atmosphere for comparison (N.O.A.A, 1976). To perform the time-dependent correction, users may import their own geomagnetic database for paleomagnetic corrections or opt for one of the three proposed datasets (Lifton, 2016; Lifton et al., 2014; Muscheler et al., 2005).For the important choice of the production rate, CREp is linked to a database of production rate calibration data that is part of the ICE-D (Informal Cosmogenic-nuclide Exposure-age Database) project (http://calibration.ice-d.org). This database includes published empirical calibration rate studies that are publicly available at present, comprising those of the CRONUS-Earth and CRONUS-EU projects, as well as studies from other projects. In the present study, the efficacy of the different scaling models has also been evaluated looking at the statistical dispersion of the computed Sea Level High Latitude (SLHL) production rates. Lal/Stone and LSD models have comparable efficacies, and the impact of the tested atmospheric model and the geomagnetic database is also limited.Users however have several possibilities to select the production rate: 1) using a worldwide mean value, 2) a regionally averaged value (not available in regions with no data), 3) a local unique value, which can be chosen among the existing dataset or imported by the user, or 4) any combination of multiple calibration data.If a global mean is chosen, the 1σ uncertainty arising from the production rate is about 5% for ¹⁰Be and 10% for ³He. If a regional production rate is picked, these uncertainties are potentially lower.CREp is able to calculate a large number of ages in a reasonable time (typically < 30 s for 50 samples). The user may export a summary table of the computed ages and the density probability function associated with each age (in the form of a spreadsheet).     

大连市区地表天然放射性水平调查

利用ARD型γ能谱仪对辽宁省大连市区地表天然放射性核素²³⁸U、²³²Th、⁴⁰K含量进行了现场测量.调查结果显示,大连市区²³⁸U、²³²Th、⁴⁰K比活度平均值分别为23.09 Bq/kg（范围值1.24~151.91 Bq/kg）、18.99 Bq/kg（范围值0.41~92.57 Bq/kg）、386.39 Bq/kg（范围值31.30~1095.50 Bq/kg）,均显著低于全国和世界的平均值.在测得的²³⁸U、²³²Th、⁴⁰K含量基础上,计算了距地面1 m高处空气中γ辐射吸收剂量率、外照射指数、内照射指数和年有效剂量等参数,并据此对大连市区天然放射性水平进行了评价.空气中γ辐射吸收剂量率（Dr）平均值为39.04 nGy/h,远低于全国（81.5 nGy/h）和世界（80 nGy/h）平均水平.外照射指数、内照射指数平均值分别为0.23、0.12,均远小于国家对建筑材料外照射指数的限值1.年有效剂量为0.048 mSv,远低于世界年平均有效剂量（0.46 mSv）以及公众外照射年有效剂量（1.0 mSv）的限值.评价结果表明,大连市区地表天然放射性辐射处于安全的水平.     

变化环境下中国东南沿海致灾气旋及其人口暴露度研究

本文基于气象观测站的逐日气压、风速和降水量确定致灾气旋阈值,结合区域气候模式COSMO-CLM (CCLM)输出,研究中国东南沿海地区2021—2050年RCP2.6、4.5、8.5情景下致灾气旋的时空变化特征。并采用人口-发展-环境分析模型(PDE),预测共享社会经济路径SSP2下东南沿海地区人口发展趋势,揭示了致灾气旋人口暴露度演变。研究表明:(1) RCP2.6情景,东南沿海地区平均每年发生致灾气旋6.3次,风速和降水量较基准期(1986—2005年)分别增加9%和15%,72%区域致灾气旋人口暴露度有所增加。暴露在超基准期最大影响面积和最强风速下的致灾气旋人口分别增加2.1亿和0.1亿。(2) RCP4.5情景,致灾气旋年均发生7次,风速和降水量较基准期分别上升16%和32%,89%地区致灾气旋暴露人口增加。暴露在超基准期最大影响面积和最强风速下的致灾气旋人口分别增加2.6亿和0.5亿。(3) RCP8.5情景,致灾气旋年均发生5.8次,风速和降水量较基准期分别增加32%和50%,65%区域致灾气旋暴露人口度有所增加。暴露在超基准期最大影响面积和最强风速下的致灾气旋人口分别增加5.7亿和1.9亿。(4)相比RCP2.6,RCP8.5情景致灾气旋风速和降水量高出23%和35%,暴露于超基准期最大影响面积和最强风速的致灾气旋人口分别多3.6亿和1.8亿。控制温室气体浓度对降低致灾气旋的不利影响具有重要意义。     

黄、东海溶解态无机砷的分布及其季节变化

本文综合2000～2003年期间9个航次的研究结果,讨论了总溶解态无机砷（TDIAs,[TDIAs]=[As^5＋]＋[As^3＋]）和亚砷酸盐（As^3＋）在黄、东海的分布和季节性变化。调查海区覆盖了黄、东海不同水文和化学性质的区域,研究重点放在自长江口向东南琉球群岛沿伸的PN断面以讨论陆源输送的物质对中国陆架边缘海的影响。利用氢化物发生原子荧光光谱法（HG-AFS）分析砷的不同形态（TDIAs,As^3＋）。TDIAs受河流陆源输送的影响在近岸区域含量较高,并随着离岸距离的增加含量逐步下降。在东海陆架坡折带的近底层水中也存在TDIAs的高值中心,此区域具有低温、高盐、低悬浮颗粒物含量的特征,显示出入侵陆架的黑潮水是陆架区TDIAs另一个主要的源。TDIAs的季节性变化趋势受到长江冲淡水水量及黑潮入侵陆架强度的季节及年际变化共同影响。研究区域中As^3＋的分布特征与TDIAs相反,其含量、分布及季节性变化受到浮游植物活动的影响,表现出与叶绿索含量存在正相关关系。夏季东海陆架PN断面中As／P的化学计量比值约为2×10^3。黄、东海溶解态砷的含量与世界其它海区相近,表明其未受到明显人为活动的影响。     

一种自适应快速曝光控制方法

针对在快速运动中连续高速地获取高质量的图像信息,提出了一种基于光圈优先的自动曝光控制方法。通过对初始图像的评估,确定当前景物亮度下最佳光圈大小,进而获得此光圈下不同景物亮度的曝光时间,由此建立景物亮度与曝光时间的关系模型。在实际运用中根据关系模型,通过跟踪当前景物亮度动态调整曝光时间以达到获取最佳曝光量的目的。该方法具有实时、快速、成像质量高和控制精确可靠的特点,并在实际应用中得到验证。