Collisional excitation of interstellar cyclopropenylidene

Theoretical rotational excitation rates were computed for C3H2 in collisions with He atoms at temperatures from 30 to 120 K. The intermolecular forces were obtained from accurate self-consistent field and perturbation theory calculations, and collision dynamics were treated within the infinite-order sudden approximation. The accuracy of the latter was examined by comparing with the more exact coupled states approximation.     

Histopathological biomarkers in estuarine fish species for the assessment of biological effects of contaminants

The increasing emphasis on the assessment and monitoring of estuarine ecosystems has highlighted the need to deploy appropriate biological indices for these locations. Fish diseases and histopathology, with a broad range of causes, are increasingly being used as indicators of environmental stress since they provide a definite biological end-point of historical exposure. This study reports on the histopathological alterations observed in selected organs and tissues of three species of estuarine fish (Platichthys flesus, Pomatoschistus minutus and Zoarces viviparus), captured from four British estuaries (the Tyne, Tees, Mersey and Alde), differently impacted by contaminants, including PAHs. A biannual sampling regime was used to identify the important seasonal variations that occur in terms of the observed biological effects. Inflammatory lesions and hepatocellular fibrillar inclusions attained their highest prevalence in P. flesus captured from the Tyne, Tees and Mersey. The presence of pre-neoplastic and neoplastic toxicopathic lesions was highest in P. flesus captured from these sites, when compared to fish from the Aide reference site. In particular, the prevalence of hepatic foci of cellular alteration (up to 43.3%) and hepatocellular adenoma (up to 10%) were highest in P. flesus captured from the Mersey estuary. Intersex (ovotestis) was only recorded in male P.flesus captured from the Mersey estuary (up to 8.3%) and from male Z. viviparous captured from the Tyne estuary (25%). Pathologies associated with the gill and the kidney were also most prevalent in fish captured from the Tyne, Tees and Mersey estuaries. This study has successfully applied histopathology to an estuarine monitoring program, both for the recording of toxicopathic lesions in the liver and other organs, and for the detection of the endpoint of endocrine disruption, intersex. As such, it provides a powerful integrative tool for the assessment of biological effects of contaminants in these environments.     

下地壳基性麻粒岩流变强度实验研究

镁铁质基性麻粒岩被认为可能是大陆下地壳的主要组成岩石[1,2],涉及当前地球动力学研究中地壳变形和高原隆升,壳幔边界的力学耦合与拆离,底侵和拆沉作用等一系列地球动力学问题阳[3,4],具有重要的地球动力学意义.大陆下地壳的流变学性质是我们深入认识这些地球深部过程的关键点之一.     

饶拔寨榴辉岩绿辉石中镁铁闪石及单斜钠长石出溶体

近年来,在北大别杂岩带中发现了榴辉岩[1～3]及榴辉岩相岩石[4,5],岩石地球化学及Sm-Nd和U-Pb同位素特征[6,7]证明,北大别杂岩带大多数属印支期扬子俯冲陆壳的一部分,引起了国内外学者的关注.相对于南大别超高压带中榴辉岩来说,北大别榴辉岩经历了麻粒岩相退变质阶段和燕山期热变质事件的影响,形成大面积强烈退变和相应的退变质显微构造.     

The geography of dual career households: a research agenda and selected evidence from secondary data sources for Britain

"Amongst the key dimensions of population and labour market change in most parts of western Europe and other similar economies in the 1990s are low fertility rates, rising numbers of smaller households, increasing female participation rates, growth in higher level non-manual occupations and the spread of flexible employment patterns. This paper explores how these trends have led to an increase in the number and significance of one particular subgroup: dual career households. An overview from available secondary sources of the geography and socio-economic characteristics of such households in Britain is presented, and directions for possible future research on dual career households are outlined."     

中国大陆科学钻探终孔及研究进展

中国大陆科学钻探工程经过1309天的努力奋斗，于2005年1月23日，钻井终孔深度达到5118．20m。成为中国钻探技术发展的新里程碑。全面研究正在开展，在巨量物质深俯冲、超高压深俯冲与折返的精确定年、超高压岩石的原岩形成背景、上地幔流变学、地幔特殊新矿物发现、地下流体异常及地下微生物发现等方面已取得重要进展。     

中国大陆科学钻探（CCSD）主孔地区岩石圈热结构

岩石圈热结构是指地球内部热量在壳幔的配分比例、温度以及热导率和生热率等热学参数在岩石圈中的分布特征。岩石圈的热结构直接影响着岩石的物理性质和流变学性质,同时还控制了化学反应的类型和速度,从而制约着岩石圈的发展和演化。本文在前人CCSD主孔岩石主、微量元素研究基础上,利用Rybach生热率公式计算了钻孔岩石的放射性生热率,并结合岩石热导率的测定研究了CCSD主孔100-2000m岩石的热结构和主孔榴辉岩在不同退变质程度下生热率、热导率的变化:钻孔中岩石的平均生热率为0.95μWm-3,平均热导率为2.96mWm-1K-1。,其中片麻岩生热率高迭1.01-1.7μWm-3,热导率为2.76-2.96mWm-1K-1;基性超基性岩石生热率最低(<0.21μWm-3),热导率则高达3.20mWm-1K-1以上;新鲜榴辉岩生热率、热导率居中,分剐为0.16-0.44μWm-3和3.31-3.85mWm-1K-1。钻孔中榴辉岩生热率、热导率变化主要受岩性控制:从新鲜榴辉岩到完全退变榴辉岩,热导率总体上降低,但从强退变榴辉岩到完全退变榴辉岩,岩石热导率升高;而在此过程中岩石生热率总体上升高,仅当从中等退变质榴辉岩退变为强退变质榴辉岩时,岩石生热率出现降低趋势。在综合研究的基础上预测CCSD主孔5000m深度处温度为139℃,温度范围为131-151℃。根据区域深部地球物理探测成果对CCSD主孔地区岩石圈热结构进行了研究:上地壳底部温度为256℃,中地壳底部温度为492℃,Moho面温度为683℃,岩石圈底部温度为1185℃,来自地幔的热流为44.1mWm-2,对地表热流的贡献率为58%。研究结果表明,由岩石物理方法获得的CCSD主孔地区岩石圈地温曲线与石榴石-二辉橄榄岩包体推断的中国东部地温曲线十分吻合,本文从实验岩石物理学角度为CCSD主孔地区岩石圈热结构研究提供了重要约束     

鲁东官山榴辉岩与围岩接触关系的新发现及其对年代学的启示

鲁东官山榴辉岩呈透镜状包于变质含霓石碱性花岗岩中,榴辉岩的片麻理与主岩片麻理总体呈交切关系,局部可见变质含霓石碱性花岗岩呈细小岩枝状脉贯入榴辉岩中。变质含霓石碱性花岗岩锆石U-Pb法下交点年龄为231±25 Ma,上交点年龄为818±66 Ma。发现了闪长玢岩脉斜切式侵入榴辉岩及变质含霓石碱性花岗岩的接触关系,且闪长玢岩脉中有榴辉岩捕虏体,这种现象指示:闪长玢岩侵位时榴辉岩已折返至地壳较浅部位。研究表明,榴辉岩与变质含霓石碱性花岗岩共同经历了新元古代的超高压变质作用,但变质作用发生时含霓石碱性花岗岩可能处于熔融状态,榴辉岩是其中的固相包体。     

榴辉岩中石英出熔体的拉曼光谱学研究及其构造意义

利用拉曼光谱学和费氏台方法对若干地区超高压榴辉岩中柯石英和榴辉岩中石英出溶体的超显微构造特征进行了研究。研究结果表明，石榴石（或绿辉石）中柯石英向石英相变是一个连续变化过程。绿辉石中石英出溶体和主晶具有一定的晶体学拓扑关系，即石英出溶体长轴有两个展布方向：平行于绿辉石（100）裂理面和平行于绿辉石（－101）面。目前，部分学者推断榴辉岩绿辉石中石英出溶体可作为超高压变质作用的标志。笔者认为，棒状定向石英在绿辉石中出溶的温压条件和出溶机理尚未查明。因此，需加强过量二氧化硅单斜辉石出溶机理的超高压实验研究，从而为证实石英出溶体作为超高压标志提供实验定量约束。     

大别-苏鲁榴辉岩和石榴辉石岩中矿物Ce异常: 对氧化环境下形成沉积物深俯冲作用的示踪

准分子激光ICP-MS矿物原位微区分析发现, 来自大别-苏鲁超高压变质带典型地区(双河、毛屋、碧溪岭及仰口)的榴辉岩和石榴辉石岩中石榴石Ce异常从正到负高度变化. 绿辉石或单斜辉石也表现出类似的Ce异常特征, 但变化幅度小于石榴石. 这种Ce异常高度变化的现象仅见于氧化条件下形成的强烈风化剖面中. 因此, 这一结果表明大别-苏鲁榴辉岩和石榴辉石岩中存在氧化条件下形成的风化沉积物, 这些陆壳物质的深俯冲对地幔的改造和物质再循环可能具有重要意义.