华南李家沱剖面寒武纪纽芬兰世海水氧化还原性质演化及其驱动因素

大气-海洋含氧量的演化对埃迪卡拉纪-寒武纪转折期的后生动物大爆发事件具有重要影响.为探讨寒武纪纽芬兰世中国南方海洋氧化还原性质的演化及其初级生产力、海水硫酸盐浓度等演化驱动因素, 分析了李家沱剖面纽芬兰世留茶坡组和小烟溪组微量元素、有机碳含量、有机碳同位素、总硫含量、黄铁矿硫同位素等.该剖面沉积于斜坡-盆地环境且出露齐全.该剖面上V/Sc、Th/U及Mo、U、V、Ni、Cu等元素的富集系数呈现出5个变化旋回, 其中留茶坡组中上部和小烟溪组中部各存在一氧化环境段, 其余层段处于缺氧环境, 而Re/Mo则显示仅在小烟溪组中部水体出现过短暂的氧化环境和含有游离H₂S的硫化环境, 其余层段处于没有游离H₂S的缺氧非硫化环境.Ba、Ni、Cu、Zn、Cd等微量元素的富集系数及TOC表明: 留茶坡组的有机质沉降量和埋藏量都明显小于上覆小烟溪组; 而在小烟溪组中, 其中部有机质的沉降量和埋藏量最低, 下部最高, 上部次之.TOC/TS、TS以及黄铁矿硫同位素的垂向演化趋势等都显示李家沱剖面纽芬兰世大都处于低海水硫酸盐浓度环境.低海水硫酸盐浓度是造成李家沱剖面纽芬兰世缺氧水体未富集游离H₂S的主要原因.大气含氧量的升高是导致李家沱剖面小烟溪组中部出现短暂氧化环境以及近硫化环境的主要原因.      

Summertime Surface N_2O Concentration Observed on Fildes Peninsula Antarctica:Correlation with Total Atmospheric O_3 and Solar Activity

Three-year summertime surface atmospheric N2O concentrations were observed for the first time on the Fildes Peninsula, maritime Antarctica, and the relationships among the N2O concentration, total atmospheric O3 amount, and sunspot number were analyzed. Solar activity had an important effect on surface N2O concentration and total O3 amount, and increases of sunspot number were followed by decreases in the N2O concentration and total O3 amount. A corresponding relationship exists between the N2O concentration and total atmospheric O3, and ozone destruction was preceded by N2O reduction. We propose that the extended solar activity in the Antarctic summer reduces the stratospheric N2O by converting it into NOx, increases the diffusion of N2O from the troposphere to the stratosphere, decreases the surface atmospheric N2O, and depletes O3 via the chemical reaction between O3 and NOx. Our observation results are consistent with the theory of solar activity regarding the formation of the Antarctic O3 hole.     

广西贵港六梅金矿地球化学研究

广西贵港六梅金矿床位于贵港市龙山矿田福六岭金矿区,为微细浸染型金矿床。矿床中主要矿石矿物为毒砂和黄铁矿。通过载金矿物毒砂和黄铁矿含金性、金浸出提取、晶体结构测定等方法,查明矿床的金存在形式。浸出率试验中平衡计算表明,载金矿物毒砂中的晶格金形式约占25%,超显微包体形式金约为75%。矿床流体包裹体测温和稀土元素地球化学研究表明,六梅金矿床为中-低温热液型矿床,成矿物质来源与地层有关。     

Implications of global emission policy scenarios for domestic agriculture: a New Zealand case study

Agricultural GHG mitigation policies are important if ambitious climate change goals are to be achieved, and have the potential to significantly lower global mitigation costs [Reisinger, A., Havlik, P., Riahi, K., van Vliet, O., Obersteiner, M., & Herrero, M. (2013). Implications of alternative metrics for global mitigation costs and greenhouse gas emissions from agriculture. Climatic Change, 117, 677–690]. In the post-Paris world of ‘nationally determined contributions’ to mitigation, the prospects for agricultural mitigation policies may rest on whether they are in the national economic interest of large agricultural producers. New Zealand is a major exporter of livestock products; this article uses New Zealand as a case study to consider the policy implications of three global policy scenarios at the global, national and farm levels. Building on global modelling, a model dairy farm and a model sheep and beef farm are used to estimate the changes in profit when agricultural emissions are priced and mitigated globally or not, and priced domestically or not, in 2020. Related to these scenarios is the metric or GHG exchange rate. Most livestock emissions are non-CO₂, with methane being particularly sensitive to the choice of metric. The results provide evidence that farm profitability is more sensitive to differing international policy scenarios than national economic welfare. The impact of the choice of metric is not as great as the impact of whether other countries mitigate agricultural emissions or not. Livestock farmers do best when agricultural emissions are not priced, as livestock commodity prices rise significantly due to competition for land from forestry. However, efficient farmers may still see a rise in profitability when agricultural emissions are fully priced worldwide.

Policy relevance

Exempting agricultural emissions from mitigation significantly increases the costs of limiting warming to 2 °C, placing the burden on other sectors. However, there may be a large impact on farmers if agricultural emissions are priced domestically when other countries are not doing the same. The impacts of global and national climate policies on farmers need to be better understood in order for climate policies to be politically sustainable. Transitional assistance that is not linked to emission levels could help, as long as the incentives to mitigate are maintained. In the long run, efficient farmers may benefit from climate policy; international efforts should focus on mitigation options and effective domestic policy development, rather than on metrics.     

扰动位能理论及其应用——扰动位能的概念、表达及其时空结构

针对局地环流能量转换问题,该工作系列讨论扰动位能理论及其应用.此文是第一篇,提出了扰动位能的新概念,将其分解为大气扰动位能(简称扰动位能)和表面扰动位能两个部分,给出了扰动位能各阶矩项的数学表达形式,结合资料指出二阶以上的扰动位能高阶矩项相对于其一阶矩项和二阶矩项来说是小量,可忽略,并指出扰动位能二阶矩项的全球平均恰好等于传统的有效位能,但两者在物理意义上明显不同.结合NCEP/NCAR再分析资料,研究了扰动位能的时空结构以及与大气动能之间的联系.扰动位能一阶矩项在热带地区为正、高纬度地区为负; 二阶矩项在热带和高纬度地区出现极大值,在副热带及中纬度地区出现极小值,即在南北方向上呈现三峰二谷的特征; 在局地上,由于一阶矩项在数值上较二阶矩项绝对占优,因此,扰动位能的分布与其一阶矩项的情形相似.在垂直方向上,扰动位能主要集中在对流层下层,其数值随高度的增加而迅速减少,在50 hPa以上均可以忽略不计.扰动位能有明显的季节变化,其在高纬度地区在冬半球比夏半球大很多; 南、北半球平均的扰动位能一阶矩项季节变化的幅度约是相应二阶矩项的二十倍.随着季节变化扰动位能定常波的槽脊在北半球有显著的东西方向移动,而在南半球则只表现为振幅上的增减.分析表明,从区域或局地尺度上大气动能的季节变化与扰动位能一阶矩项的关系密切,二者呈显著反向变化关系,而与二阶矩项的关系不确定; 但在全球或半球尺度上,大气动能与扰动位能二阶矩项的比率随季节基本保持不变,约是20%.此外,对大气总动能时空结构的分析也得到了与前人不同的新结果.关于利用此文提出的概念和理论对局地环流能量收支的分析、表面扰动位能的作用以及它们在大气环流变化研究中的应用,将在以后的文章中给出.     

潍河流域下游地表污水对地下水水质影响的状态分析

为了准确地建立莱洲湾南岸地区虞河段地表水与地下水污染质运移的数学模型,本文对研究区地下水及地表水污染特征及其污染现状进行了调查、分析,为地下水资源的合理利用开发提供了依据。     

大肠杆菌O157:H7的活的非可培养状态

将大肠杆菌 O157:H7培养于低温贫养条件下 ,以涂布平板法 (PC)和最大近似值法(MPN)检测可培养细菌数 ,95～ 115d后表明可培养菌数下降为零。吖啶橙荧光显微镜直接计数法(AODC)检测细菌总数 ,表明细菌总数始终变化不大 ,而活菌直接镜检计数 (DVC)检测到的活菌数保持在 10 6个 / m L。实验证明了大肠杆菌 O157:H7在一定的条件下可进入活的非可培养状态(VBNC)。     

Methodology for Rare Earth Element Determinations of Uranium Oxides by Ion Microprobe

A methodology for the determination of the rare earth elements in uranium oxides by ion microprobe has been set up on a Cameca ims-3f instrument. An uranium oxide reference material from a syn-metamorphic uranium deposit related to albitisation has also been developed for this type of analysis. Applications of the methodology are presented for a series of uranium oxides selected from some major uranium deposit types: from the world's highest grade unconformity-related uranium deposit from the Athabasca Basin (Saskatchewan, Canada; the Shea Creek and the McArthur River examples), a perigranitic vein-type deposit (Pen Ar Ran, Vendée, France) and a volcanic caldera-related deposit (Streltsovkoye, Transbaikalia, Russia). Each type of uranium deposit appears to have a specific REE signature. All REE patterns from the Shea Creek and the McArthur deposits are characterised by bell-shaped patterns centred on Tb-Dy and similar to those already published for uranium oxides from unconformity-related deposits from Australia. Such bell-shaped REE patterns centred on Tb-Dy may therefore be considered as a typical signature of uranium oxides from Mesoproterozoic unconformity-related deposits. A smoother bell shape pattern centred on Eu characterises the syn-metamorphic albitisation related deposit of Mistamisk selected for the reference material. The REE patterns from the Pen Ar Ran deposit show a fractionation from LREE to HREE with anomalously high abundances of Sm, Eu and Gd with respect to the other REEs, similar to the REE patterns of uranium oxides from the volcanic-related deposits of Streltsovkoye.     

Relational places of ethnic Burman women migrants in the borderland town of Tachilek, Myanmar

This paper presents an investigation based on the testimonies of ethnic Bamar or Burman women migrant workers in the ethnically diverse 'borderland' town of Tachilek, Myanmar and interviews with their relatives in the home village in the central Burman heartlands. We examine how the concept of relational places, here involving a village in the central Mandalay Division and a town in the Myanmar–Thailand borderland, is related to differential power relations affecting the women migrants. We focus on the ways that gender identity and social position are limited by the relational places of community elders and the migrant women themselves, and suggest that the relational places of migrants in Myanmar are constructed through the nexus of varied forms of state control in both the central Burman heartlands and the multiethnic borderlands of the country.