乙酸乙酯对三角褐指藻生长的影响

以三角褐指藻为研究对象,研究了不同质量浓度的乙酸乙酯对其生长的影响。结果表明,在质量浓度低于1.8g/L时,乙酸乙酯对三角褐指藻的生长不产生负面影响,并能提高三角褐指藻的细胞密度和部分脂肪酸的质量分数。其中,细胞密度提高了35%,C18∶0、C18∶2和C20∶5等几种具有经济价值的脂肪酸在总脂肪酸中所占的质量分数分别提高了15.32%,23.15%和31.13%。另外,光合作用活性测定结果表明,加入乙酸乙酯后,三角褐指藻的最大光合作用速率P_max降低、呼吸作用速率R_d增加,这证明了乙酸乙酯是以有机碳源的形式被藻细胞利用,三角褐指藻以混合营养的方式生长。     

化石、矿物和岩石样品的Sm—Nd同位素实验方法研究及其应用

本文详细介绍了化石、矿物和岩石样品中Sm—Nd同位素化学制备与质谱测定实验技术。样品采用Teflon密闭熔样法,用阳离子交换程序分离Sm和Nd。采用钽/铼三灯丝和多接受技术在VG354质谱计上以Sm~+和Nd~+形式测定Sm和Nd。Nd同位素比值以 ~(146)Nd/~(144)Nd=0.7219为标准化值。对BCR—1岩石标样测定为~(143)Nd/~(144)Nd=0.512662±8(2σ_m)。Nd全流程本底为5—7×10~(-11)克。采用上述实验方法研究了中国大阳岔国际寒武/奥陶系界线候选层型剖面中古生物化石 Sm—Nd同位素体系,取得了可靠的数据和有意义的地质结论。     

广西六寨中泥盆世生物礁基底层内的Pseudomicroplasma—Cystiphylloides群落及其相关问题的探讨

分析记述的Ｐｓｅｕｄｏｍｉｃｒｏｐｌａｓｍａ—Ｃｙｓｔｉｐｈｙｌｌｏｉｄｅｓ群落，保存于广西六寨中泥盆统东岗岭组生物礁基底层内；至少由十一大门类的４９个居群组成；生物生活方式有六种；动物进食类型有四种；由三个营养级构成群落的营养结构；生物生活取食位置在垂向空间上具有四个层次；Ｐｓｅｕｄｏｍｉｃｒｏｐａｓｍａ、Ｃｙｓｔｉｐｈｙｌｌｏｉｄｅｓ是优势生物和特征生物；底栖固着、悬食、中位生活取食层次、初级消费者营养级等为群落的主要生态特征。该化石群落所代表的原生群落，生存于中泥盆世吉维特期的早期，发育于水流畅通地势较为平坦的浅海陆棚环境（风暴浪基面以上的潮下带）。该化石群落的特征反映的是其原生群落中底栖动物群的生态特征。原生群落的消亡与群落演替有关。     

基于灰色关联模型的我国三大化石能源消费研究

在对中国统计年鉴2000-2011年的分行业能源消费数据进行归类统计的基础上,构建了我国七大行业对三大化石能源消费数据与总消费数据之间的序列数表.运用灰色关联度评价法对序列数表之间的关联度做定量计算.结果显示,我国的三大化石能源消费主要在工业、制造业、电力、建筑业等第二产业中,消费结构不合理,我国应在保证能源提供充足的前提下加快洁净煤技术的研发,调整消费结构,充分利用天然气资源.以完善产业结构、发展循环经济、实施清洁生产等一系列措施保证我国能源高效、清洁、可持续利用.     

Caecilian viviparity and amniote origins: a reply to Wilkinson and Nussbaum

An evaluation of the evolution of reproduction in amniotes by the authors has been recently criticized. This criticism is shown to be based on a misrepresentation of our work. The ancestral amniote was certainly oviparous, but this does not necessarily imply that eggs were laid at an early stage of development. The presence of a significant amount of intrauterine development in the earliest amniotes remains as parsimonious as the alternative, despite recent claims to the contrary. The relative rarity of amniote groups that laid heavily mineralized egg membranes in the Palaeozoic may explain why no amniote fossil egg has been found in the Palaeozoic.     

Molecular insights into the novel aspects of diatom biology

Diatoms are unicellular photosynthetic eukaryotes that are thought to contribute as much as 25% of global primary productivity. In spite of their ecological importance in the worlds oceans, very little information is available at the molecular level about the novel aspects of their biology. Recent advances, such as the development of gene transfer protocols, are now allowing the genetic dissection of diatom biology. Notable examples are advances in understanding the genetic basis for the silica-based bioinorganic pattern formation of their cell walls and for elucidating key aspects of diatom ecophysiology. The potentiation of current research will allow an evaluation of the use of diatoms to construct submicrometre-scale silicon structures for the nanotechnology industry and will reveal the molecular secrets underlying their ecological success. Received 29 March 2001; received after revision 31 May 2001; accepted 31 May 2001     

Late Holocene paleoenvironmental changes in the southern Okinawa Trough inferred from a diatom record

We analyzed sediment diatoms from core MD05-2908 to infer climate and paleoenvironmental changes in the southern Okinawa Trough (SOT) over the past 1000 years.Because the study area is located in the East Asia monsoon area and beneath the main axis of Kuroshio Current,the climatic and hydrographical conditions are strongly influenced by both of these factors.The species used as environmental indicators,including the Kuroshio Current species (KC species) and freshwater species,were investigated in this paper.Changes in the abundance of the two groups of species revealed significant variations in water temperature and hydrography in the SOT during the Medieval Warm Period (MWP) and the Little Ice Age (LIA).From 950-1500 AD,the abundance of the KC species increased fluctuantly,while the freshwater species decreased,showing that the influence of the Kuroshio Current was intensified at that interval and the precipitation of the study area was relatively low.The KC species decreased remarkably and was maintained at a low abundance during the interval of 1500-1900 AD,which suggests that the impact of the Kuroshio Current on the SOT weakened during the period corresponding to the LIA.Moreover,the high abundance of the freshwater species at the same interval indicates a distinct increase in precipitation in northeastern Taiwan,which may be correlated to the south-detention of the rainfall belt in China caused by the southward migration of the western Pacific subtropical high.     

Bio-manufacturing technology based on diatom micro- and nanostructure

Diatom frustules,considered as novel bio-functional materials,display a diversity of patterns and unique micro-and nanostructures which may be useful in many areas of application.Existing devices directly use the original structure of the biosilica frustules,limiting their function and structural scale.Current research into the shapes,materials and structural properties of frustules are considered;a series of frustule processing methods including structure processing,material modification,bonding and assembly techniques are reviewed and discussed.The aim is to improve the function of diatom frustules allowing them to meet the design requirements of different types of micro devices.In addition,the importance of the comprehensive use of diatom processing methods in device research is discussed using biosensors and solar cells as examples,and the potential of bio-manufacturing technology based on diatom frustules is examined.