Suitability of Mn‐ and Fe‐Rich Reference Materials for Microanalytical Research

Manganese‐ and iron‐rich materials are of major geoscientific and economic interest, many of which contain microscopic features that provide valuable information. To obtain accurate results, a homogeneous microanalytical reference material for calibration is needed. Several researchers have used the Mn‐ and Fe‐rich RMs, JMn‐1, NOD‐A‐1, NOD‐P‐1 and FeMn‐1, for this purpose; therefore, they were tested in this study to determine their suitability for microanalysis. Their homogeneity was investigated by laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) with two different types of lasers (nano‐ and femtosecond), with spot and line scan analyses and with different operating parameters, such as spot size, pulse repetition rate and fluence. As the established manganese nodule RMs revealed inhomogeneities for picogram to microgram test portions, we also investigated the new synthetic Fe‐ and Mn‐rich RM, FeMnOx‐1. FeMnOx‐1 was found to be homogeneous for large (ø 40 μm: 2% RSD repeatability) and small (ø 8–10 μm: 10% RSD repeatability) spot sizes. This homogeneity is in the range of the homogeneous NIST SRM 610 and GSE‐1G reference glasses. Furthermore, FeMnOx‐1 revealed a large‐scale homogeneity within uncertainties of a few per cent, using test portions in the ng range, when measuring four individual mounts of this material.     

Precise Determination of Sm and Nd Concentrations and Nd Isotopic Compositions in Highly Depleted Ultramafic Reference Materials

In this study, a high‐precision method for the determination of Sm and Nd concentrations and Nd isotopic composition in highly depleted ultramafic rocks without a preconcentration step is presented. The samples were first digested using the conventional HF + HNO₃ + HClO₄ method, followed by the complete digestion of chromite in the samples using HClO₄ at 190–200 °C and then complete dissolution of fluoride formed during the HF decomposition step using H₃BO₃. These steps ensured the complete digestion of the ultramafic rocks. The rare earth elements (REEs) were separated from the sample matrix using conventional cation‐exchange chromatography; subsequently, Sm and Nd were separated using the LN columns. Neodymium isotopes were determined as NdO⁺, whereas Sm isotopes were measured as Sm⁺, both with very high sensitivity using single W filaments with TaF₅ as an ion emitter. Several highly depleted ultramafic rock reference materials including USGS DTS‐1, DTS‐2, DTS‐2b, PCC‐1 and GSJ JP‐1, which contain extremely low amounts of Sm and Nd (down to sub ng g^?1 level), were analysed, and high‐precision Sm and Nd concentration and Nd isotope data were obtained. This is the first report of the Sm‐Nd isotopic compositions of these ultramafic rock reference materials except for PCC‐1.     

A New Basal Titanosaur (Dinosauria: Sauropoda) from the Early Cretaceous of China

A new dinosaur of Early Cretaceous age was recently discovered from the Mazongshan area of northwestern Gansu Province, China. The new dinosaur represents a new genus and species of Sauropoda, and is among the most basal members of Titanosauria. Its finding also suggests that titanosaurs might have originated in Asia no later than the Early Cretaceous.     

太湖新银鱼、鲚鱼的食性比较及相互影响分析

在太湖,通过对263个太湖新银鱼和鲚鱼胃含物样本的食物组成分析和比较,研究了两种鱼类间的食物关系;并结合太湖历年鱼类渔获量资料,对渔获量变化间可能存在的相互影响进行了偏相关分析.结果表明:太湖新银鱼在4月份的食物中以桡足类为主,占个数的70.11%±10.57%,其次是枝角类,为29.84%±10.62%,轮虫的数量极少,仅占0.05%±0.11%;在4月份1 鲚鱼的食物中以枝角类为主、占79.35%±11.42%,桡足类占19.97%±10.78%,而轮虫和虾的数量很少,分别占0.49%±0.45%和0.20%±0.44%.而在9-10月份0 鲚鱼的食物中,枝角类占89.77%±13.69%,桡足类占7.84%±11.53%,轮虫占2.39%±4.95%;用Pianka提出的公式,计算两种鱼类在4月份5个采样点的饵料重叠系数平均为0.4739±0.2810,没有达到Keast提出的Ojk＞0.7的严重重叠水平;计算5个采样点的相同食物组成比平均为46.42%±20.32%,和饵料重叠系数接近.而偏相关分析表明:两种鱼类数量变化间的相关关系是负向的,且随着鱼类密度的增加,负相关关系的显著水平有不断提高的趋势.如1973-1984年期间的负相关关系远没有达到显著水平(r=-0.2531 p=0.584),而1985-2004年期间的负相关关系接近显著水平(r=-0.4395 P=0.101).分析认为:太湖新银鱼和鲚鱼的食物虽有重叠,但通常情况下食物竞争并不激烈;种群数量变化间的相互影响是负向的,没有达到显著水平.可能仅在两种鱼类密度很高时,激烈地食物竞争才会发生、并主要表现为对哲水蚤和剑水蚤的竞争;且数量间负向的相互影响有加强趋势.     

铜绿微囊藻(Microcystic aeruginosa var. major)胞外酸性多糖的分离、纯化及其理化特性

通过研究太湖湖鲚的年龄结构、食物组成,结合太湖鱼类渔获量统计和环境检测资料,分析了1973-2002年间太 湖湖鲚渔获量变化的规律、原因及与生物环境间的相互关系．结果表明：1994年后湖鲚渔获量正以平均年增1430t 的速度 上升;种群中0~ 个体占99．04±2．21%(2003年)、99．08±0．80%(2004年);而0~ 湖鲚主要以浮游动物为食,其中枝角 类占食物总个数的89．77．80±13．69%．分析发现：湖鲚渔获量与 TIN、TN、COD 间的正相关关系均达到显著水平;与翘嘴 红鲌、银鱼产量间的负相关关系达到极显著水平;种群低龄化趋势加剧与捕捞强度不断升高相一致;浮游动物现存量有随 湖鲚渔获量升高而降低的趋势．     

Late-time photometry of two nearby type Ⅱ-P supernovae: 2004dj and 2004et

We present late-time photometry for two bright type Ⅱ-P supernovae (SNe) 2004dj and 2004et, extending over 400 d after the explosion, which are measured with a set of intermediate-band filters that have the advantage of tracing the strength variations of some spectral features. Although these two SNe Ⅱ-P exhibit similar photometric evolution at earlier times, they diverge during the nebular phase. SN 2004dj shows a slow late-time decline rate with ～0.7±0.1 mag (100d)-1 during the period ranging from t≈200-300 d after the explosion, while SN 2004et shows a much faster decline rate at a comparable phase, e.g., 1.3±0.1 mag (100d)-1. The steeper decay rate seen in SN 2004et is likely due to dust formation in the explosion ejecta. Based on intermediate-band photometry, we derived the evolution of the feature lines [e.g., Hα] of SNe 2004dj and 2004et which are similar in flux at comparable phases but perhaps with significantly different decay rates. The origin of the observed variations in the continuum and the feature lines is briefly discussed.     

Tracer tests in fractured rocks with a new fluorescent dye—pyrene-1,3,6,8-tetra sulphonic acid (PTS) / Tests de traçage en roches fracturées avec un nouveau produit fluorescent—l'acide pyrène 1.3.6.8 tétra sulfonique (PTS)

Abstract

Two multi-tracer tests were performed in fissured rocks accessible in underground laboratories to examine a new fluorescent dye: pyrene-1,3,6,8-tetra sulphonic acid (PTS). The first test was carried out at the Lindau Rock Laboratory (LRL), Germany, in a highly permeable ore dike, and the second, at the Grimsel Test Site (GTS), Switzerland, in a heterogeneous granite fault zone (AU 126). At the LRL new tracer was injected together with uranine in a convergent flow field (monopole test), and slightly different tracer breakthrough curves were observed according to different diffusion coefficients of both tracers. The matrix porosity calculated with the aid of the one-dimensional (1-D) single-fissure dispersion model (SFDM) agrees well with that found in earlier tracer tests and with measurements performed on core samples. At the GTS, the PTS tracer was applied together with pyranine in two-well injection–withdrawal (dipole) tests. Both tracers yielded identical tracer concentration curves, which confirm their conservative behaviour. Mathematical simulations performed with the aid of a 3-D numerical model (FRAC3DVS) yielded equally good fits for different sets of parameters, independent of whether matrix porosity was included or neglected. That lack of unique solution and the difficulty in observing the influence of matrix diffusion result from a wide distribution of the transit times of particular streamlines, which is characteristic for injection–withdrawal tests. However, both tracer tests clearly indicated that the new tracer (PTS) behaves conservatively at high pH values and can be successfully used for groundwater labelling.     

三角鲤胚后发育研究

三角鲤的胚后发育过程可分为早期仔鱼、晚期仔鱼和稚鱼3个阶段共11个时期。与其他鲤科鱼类比较,三角鲤胚后发育具卵黄囊吸收迅速、鳔迅速发育成形(巡游模式迅速建立)及鳞片的较早出现、长齐和完成胚后发育时间较短等特点;在水温为25.0±0.7℃的条件下,全长5.2±0.2 mm的初孵仔鱼经过24～26 d的发育,全长达20.6±0.3 mm即完成胚后发育;仔鱼、稚鱼的全长随日龄呈线性生长,相关方程式为L=5.8591+0.6254 A(r=0.999 2,P<0.01),每日增长约为0.63 mm。根据三角鲤胚后发育特点讨论了鱼苗生产应注意的问题。     

A New Hadrosauriform Dinosaur from the Early Cretaceous of Gansu Province, China

A new basal hadrosauriform dinosaur, Xuwulong yueluni gen. et sp. nov., is reported based on an articulated specimen including a complete cranium, almost complete axial skeleton, and complete left pelvic girdle. The specimen is recovered from the Early Cretaceous Yujingzi Basin in the Jiuquan area, Gansu Province of northwestern China. Xuwulong is among the most basal members of hadrosauriform dinosaurs, and distinguished by its unique lower jaw in having a V-shaped rostral end of the dentary in lateral view and a mandibular articular surface which levels with mid-height of the dentary ramus, as well as an enlarged and downturned prepubic process. Including Xuwulong, three basal hadrosauriforms have been discovered from the Early Cretaceous Xinminpu Group in the Mazongshan area, making it an important area to study the origin and early evolution of duck-billed dinosaurs.     

The effects of temperature and substrate on ontogenetic behavior of bastard halibut, Paralichthys olivaceus （T.et S.）

The effects of temperature and substrate on ontogenetic patterns and settlement behavior of bastard halibut, Paralichthys olivaceus （T. et S.） were studied in a series of laboratory experiments. Analysis on stage-based data revealed that except for settlement, and compared to the substrate, the ambient temperature dominantly controlled the hatch success and subsequent development of the species. The oosperm optimum survival rate of 60% during hatching occurred at 20℃, and survival rate of 29%, at 18℃ for larval rearing. The survival rate of larvae reared under variable temperature of 3.5-4.5℃ was higher than that of those reared under stable temperature. The maximum survival rate of 29%, corresponded to variation at temperature of 4℃. With increase in age newly settled juveniles preferred to lie on the fine substrate and gradually moved on the coarse substrate. GLM （general linear model） analysis showed that the combination of temperature and substrate had no significant impact on the survival of settling larvae, but definitely affected the duration of settlement.