Combined Separation of Cu,Fe and Zn from Rock Matrices and Improved Analytical Protocols for Stable Isotope Determination

Isotope ratios of heavy elements vary on the 1/10000 level in high temperature materials, providing a fingerprint of the processes behind their origin. Ensuring that the measured isotope ratio is precise and accurate depends on employing an efficient chemical purification technique and optimised analytical protocols. Exploiting the disparate speciation of Cu, Fe and Zn in HCl and HNO₃, an anion exchange chromatography procedure using AG1‐×8 (200–400 mesh) and 0.4 × 7 cm Teflon columns was developed to separate them from each other and matrix elements in felsic rocks, basalts, peridotites and meteorites. It required only one pass through the resin to produce a quantitative and pure isolate, minimising preparation time, reagent consumption and total analytical blanks. A ThermoFinnigan Neptune Plus MC‐ICP‐MS with calibrator‐sample bracketing and an external element spike was used to correct for mass bias. Nickel was the external element in Cu and Fe measurements, while Cu corrected Zn isotopes. These corrections were made assuming that the mass bias for the spike and analyte element was identical, and it is shown that this did not introduce any artificial bias. Measurement reproducibilities were ± 0.03‰, ± 0.04‰ and ± 0.06‰ (2s) for δ⁵⁷Fe, δ⁶⁵Cu and δ⁶⁶Zn, respectively.     

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.     

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 Method for Rapid Determination of Re and Os Isotope Compositions Using ID‐MC‐ICP‐MS Combined with the Sparging Method

A simple, rapid method for the determination of Re and Os concentrations and isotope compositions using isotope dilution multi‐collector inductively coupled plasma‐mass spectrometry (ID‐MC‐ICP‐MS) combined with Carius tube digestion and sparging introduction of Os was developed. For Os measurement, four channeltron ion counters to detect different Os isotopes were used simultaneously, which led to a drastic reduction in the measurement time. Rhenium isotopes were measured by means of eight Faraday cups with solution nebulisation and an ultrasonic membrane desolvator. The representative ¹⁸⁸Os count rate of an Os standard solution containing 50 pg of total Os was approximately 110000–120000 cps at the onset of measurement; the Re intensity of our in‐house 10 pg g^?1 standard solution reached 1820 V/μg g^?1 with a sample uptake rate of 95–99 μl min^?1. These values indicate that the sensitivity of the method was sufficient even for samples with low Re and Os concentrations, such as chert. As the temporal variations of the amplification efficiency of the ion counters differed from one another, we adopted a sample‐calibrator bracketing method to correct the measured Re and Os isotope ratios. The Re and Os concentrations via the isotope dilution method and the ¹⁸⁷Os/¹⁸⁸Os ratios of two sedimentary rock reference materials (JMS‐2 and JCh‐1) on the basis of the isotope ratios determined by the MC‐ICP‐MS and by negative thermal ionisation mass spectrometry (N‐TIMS) were comparable within their ranges. Based on Os isotope measurement of the IAG reference material [Durham Romil Os (DROsS)], the average difference from the recommended value and precision of Os isotope measurements by the sparging method in combination with multi‐ion‐counters were 0.72% and 0.76% [1RSD (%), n = 29], respectively. The precisions in the ¹⁸⁷Os/¹⁸⁸Os ratios [1RSD (%)] of JMS‐2, JCh‐1 and DROsS were 0.35–0.71, 1.56–3.31 and 0.99–1.28%, respectively, which depended on their Os ion intensities. No systematic difference was observed between the Re and Os geochemical compositions of JCh‐1 and JMS‐2 obtained by means of digestion with inverse aqua regia and CrO₃‐H₂SO₄ solutions, suggesting that either acid solution can be used for the sparging method of sedimentary rock samples. As CrO₃‐H₂SO₄ solution is believed to liberate predominantly the hydrogenous Re and Os fraction from organic‐rich sediment, the sparging method combined with CrO₃‐H₂SO₄ digestion and multi‐ion‐counters in the mass spectrometry is expected to be a powerful tool for reconstructing the secular change in marine Os isotope compositions with high sample throughput.     

Impacts climatiques et anthropiques sur le fonctionnement hydrogéochimique du Lac Ifrah (Moyen Atlas marocain)

Résumé

Un suivi hydrogéochimique saisonnier du Lac Ifrah (Maroc) a été réalisé au cours des années 2003–2006 dans le but de caractériser son fonctionnement hydrogéochimique vis-à-vis des impacts climatiques et anthropiques. Le Lac Ifrah a beaucoup régressé au cours de la dernière décennie. Les eaux sont relativement alcalines, oxygénées, assez turbides et sursaturées en alcalino-terreux. La charge particulaire est moyennement élevée. Le faciès hydrogéochimique est généralement de type bicarbonaté chloro-sodique magnésien. Le lac a connu un déficit hydrique important sous l'effet de la récurrence des sécheresses et de la forte pression anthropique au cours des trois dernières décennies. Ceci s'est traduit par l'élévation de la salinité des eaux impliquant une augmentation de la conductivité électrique et des teneurs en alcalins (Na⁺ et K⁺) et en chlorures. Ce déficit est évalué également par la diminution des teneurs en alcalino-terreux (Ca²⁺ et Mg²⁺) à la suite de leur précipitation sous forme de carbonates endogéniques. Les indices de saturation vis-à-vis de la calcite, de l'aragonite et de la dolomite sont toujours supérieurs à zéro. L'augmentation des éléments nutritifs (phosphore et nitrates) et la dégradation de l'oxygénation des eaux reflètent l'accélération de l'eutrophisation du lac qui est reflétée aussi par l'augmentation de la charge particulaire et la turbidité des eaux.

Editeur Z.W. Kundzewicz

Citation Etebaai, I., Damnati, B., Raddad, H., Benhardouz, H., Benhardouz, O., Miche, H. et Taieb, M., 2012. Impacts climatique et anthropique sur le fonctionnement hydrogéochimique du Lac Ifrah (Moyen Atlas marocain). Hydrological Sciences Journal, 57 (3), 547–561.     

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.     

Type IIP supernova SN 2004et: a multiwavelength study in X-ray, optical and radio

We present X-ray, broad-band optical and low-frequency radio observations of the bright type IIP supernova SN 2004et. The Chandra X-ray Observatory observed the supernova at three epochs, and the optical coverage spans a period of ∼470 d since explosion. The X-ray emission softens with time, and we characterize the X-ray luminosity evolution as   L _X∝ t ^−0.4  . We use the observed X-ray luminosity to estimate a mass-loss rate for the progenitor star of  ∼2 × 10⁻⁶ M_⊙ yr⁻¹  . The optical light curve shows a pronounced plateau lasting for about 110 d. Temporal evolution of photospheric radius and colour temperature during the plateau phase is determined by making blackbody fits. We estimate the ejected mass of ⁵⁶Ni to be  0.06 ± 0.03 M_⊙  . Using the expressions of Litvinova & Nadëzhin we estimate an explosion energy of  (0.98 ± 0.25) × 10⁵¹ erg  . We also present a single epoch radio observation of SN 2004et. We compare this with the predictions of the model proposed by Chevalier, Fransson & Nymark. These multiwavelength studies suggest a main-sequence progenitor mass of  ∼20 M_⊙  for SN 2004et.     

高压旋喷法在漂卵石冲洪积土软基处理中的应用

对于厚层的含漂卵石的山前冲洪积土软弱地基,采用常规的CFG桩、水泥搅拌桩进行地基处理,存在成孔难,复合地基承载力偏低等问题。本文以桂平市某高层商住楼工程为例,介绍了高压旋喷桩复合地基的设计和加固效果检测,结果表明,采用潜孔钻机引孔+高压旋喷桩加固技术处理含漂卵石软弱地基,能有效地解决成孔难问题,也大大提高了地基承载力和成桩效率。     

A pore-throat model based on grain-size distribution to quantify gravity-dominated DNAPL instabilities in a water-saturated homogeneous porous medium

A pore-scale network model based on spherical pore bodies and cylindrical pore throats was developed to describe the displacement of water by DNAPL. The pore body size and the pore throat size were given by statistical distributions with user-specified values for the minimum, mean and maximum sizes. The numerical model was applied to a laboratory experiment conducted on a sand-filled glass column. The parameters relative to pore body size and pore throat size that were used in the construction of the equivalent network were derived from the discrete grain-size distribution of the real porous medium. The calculated arrival times of the DNAPL front were compared with those measured using optic fibre sensors placed at different points on the control section of the experimental device. Furthermore, the model simulated DNAPL pressure measured at the entrance section of the system. In general, the numerical results obtained with the model were in good agreement with the actual measurements.     

红鳍东方鲀(Takifugu rubripes)形态性状对体重的影响效果

采用通径分析方法,对红鳍东方鲀表型形态性状对体重的影响效果进行研究.结果表明,所测各表型性状与体重之间的相关系数均达到显著水平(P＜0.05)或极显著水平(P＜0.01);体周长1对体重的直接影响(0.533)最大,对体重的决定程度(28.41％)最高,是影响体重的主要因素;全长对体重的直接作用(0.369)较大,间接作用(0.259)最小;体高、尾柄高对体重的直接作用(0.228,0.145)相对较小,主要通过体周长1的间接作用(0.363,0.296)影响体重.所选表型性状对体重的复相关指数R2=0.950,表明所选性状是影响体重的主要性状.利用逐步回归分析方法建立以体周长1、体高、尾柄高为自变量估计体重的多元回归回归方程为:y =-2154.095+42.072x1+33.936x2+72.687x3+50.538x4.