Response of estuarine meio- and macrofauna to in situ bioremediation of oil-contaminated sediment

Numerous studies have demonstrated the efficacy of bioremediation for enhancing oil removal but the ecological effect on shoreline biota is unclear. Therefore, a field experiment was designed at an intertidal sandflat in SW England to assess the effects of nutrient addition to oiled sediments on meio- and macrofauna for a period of up to 45 weeks. Natural assemblages were exposed to different types of experimental treatments (no oil, oil alone, oil treated with slow-release fertiliser or liquid fertiliser). Bioremediation stimulated the microbial population and increased oil biodegradation. This, however, did not result in faster recolonisation rates of fertilised versus non-fertilised oiled sediments. Mild effects of oil and bioremediation treatments on benthic fauna were observed, including short-term shifts in dominance patterns. Decreased abundance of dominant species in the oiled compared to unoiled sediments resulted in significantly higher evenness of benthic assemblages within the first 11 weeks of the experiment.     

A three-dimensional finite element program for brittle bimodular rock-like materials

The present paper models the behaviour of bimodular materials (materials with different tensile and compressive moduli) by using a three-dimensional finite element method. Since there is no explicit and definite expression for the shear modulus G of bimodular materials, the analysis starts with a 3 × 3 elasticity matrix in the principal stress coordinate system, and then uses a transformation from principal to Cartesian coordinates to obtain the 6 × 6 elasticity matrix. A corresponding iterative technique is proposed, and multiloading sequences in non-proportionate loading—which need more iterations because of the non-linear elastic property—are also discussed. Numerical examples are presented which show good agreement with analytical results.     

广州市国土GPS控制网联测改造数据处理与分析

扼要阐述原国土GPS控制网的情况及存在的一些问题,详细介绍国土GPS控制网联测改造方案及数据处理方法.并就一个城市的控制网改造提出一些有益的建议.     

Growing season evapotranspiration from Tamarix ramosissima stands under extreme arid conditions in northwest China

Given the increasing threat of water shortages in the extremely arid regions (rainfall<50 mm year⁻¹) of northwestern China, growing season evapotranspiration (ET) associated with native species such as Tamarix ramosissima is of particular interest. Consequently, this study sought to evaluate the accuracy of daily ET estimates using Bowen ratio data, as well as measuring seasonal ET and development of an energy balance for a stand of T. ramosissima. Bowen ratio apparatus measurements of ET were carried out on a stand of T. ramosissima in a 2.04 km² field, which are all covered with T. ramosissima near Erdaoqiao, Ejina Province, Inner Mongolia Autonomous Region, China. Soil moisture content and green area index were also monitored. Daily ET could be accurately estimated from Bowen ratio data on a continuous basis over the 153-day growing season. The mean daily T. ramosissima ET over this period was 1.62 mm day⁻¹, for a seasonal total of 248.20 mm. In this extremely arid locale, the great majority of available energy dissipated over the growing season was a result of sensible rather than latent heat fluxes. While the heat storage term was the main source of energy at night and a considerable sink of energy during the daytime, the magnitude of the daily mean soil heat flux was small. Such a determination of temporal and ecosystem-specific ET patterns allows an improved prediction of ET in the desert riparian zone.     

PAH features in the ISO SWS01 spectra of [WR] planetary nebulae

We present Infrared Space Observatory (ISO)Short Wavelength Spectrometer (SWS) observations for 16Wolf–Rayet ([WR]) planetary nebulae (PNe) in the range from 2.4 to16.5 m with the aim of analyzing the dust features present inthis group of objects. We have found that Policyclic AromaticHydrocarbon (PAH) molecular bands are present in most of the observed[WR] planetary nebulae with clear exception for K 2–16 among latetype [WC] stars.     

利用GM（1,1）预测模型预测房屋面积

房屋面积数据是地震灾害损失评估的重要参数，也是地震应急数据库基础数据。数据库要求每年及时更新，但数据更新周期较长，达不到更新要求。本研究主要从乌鲁木齐统计年鉴中提取2001—2018年房屋基础数据，建立乌鲁木齐住宅建筑总面积及人均住宅面积数据增长模型，利用GM（1,1）预测模型和多元线性回归模型预测未来2年乌鲁木齐住宅建筑总面积和人均住宅面积。本研究得到的住宅建筑总面积及人均住宅面积数据可作为应急数据库中相关基础数据更新的补充手段，也可作为未来几年震害预测的参考基础数据。     

Long-term variation in the salinity of the Southern Yellow Sea Cold Water Mass, 1976–2006

This paper discusses the long-term variation in the salinity of the Southern Yellow Sea Cold Water Mass (SYSCWM) and examines factors influencing the SYSCWM based on hydrographic datasets of the China National Standard section and the Korea Oceanographic Data Center. The mean salinity at the center of the SYSCWM showed a decreasing long-term trend. In empirical orthogonal function (EOF) analysis, the second EOF mode showed a similar long-term trend. The mean salinity of the center of the SYSCWM was related to the intrusion of saline water from the Yellow Sea Warm Current (YSWC), the salinity of the source area of the YSWC, the evaporation minus precipitation (E–P) flux, and discharge from the Changjiang River. The decreasing salinity trend to the southwest of Cheju Island produced a freshening trend in the YSWC, resulting in a reduction in the salinity of the SYSCWM. The freshening trends of the water from the northwest Pacific and the South China Sea were seen as the reason for the decreasing salinity trend from the intrusion of water into the Yellow Sea (YS). The freshwater flux influenced the surface salinity and was brought to deep layers by strong mixing in winter. The mean E–P flux signal and Changjiang River discharge signal lagged the first principal component of the SYSCWM by approximately 5 months.     

Parallel visualization of seismic wave propagation

Today parallel visualization of massive datasets from observation and numerical simulation of seismic waves is one of the major goals of geoscience community. A majority of these datasets are time-varying volume data (TVVD), also known as 4D field data. The difficulty of visualizing them on distributed parallel system mainly lies in the algorithm designing for distributed preprocessing of raw datasets, hierarchical point-to-point or collective communication implementation based on distributed data allocation, synchronous volume rendering techniques. In this work we present viable solutions for preprocessing of raw data sets, novel algorithms of parallel rendering and display matrix. Our main objective is focused on the parallel visualization of results coming from full 4D seismic wave propagation simulations.     

Radiation belt electron acceleration induced by gyroresonant interaction with magnetosonic waves

Using Cluster 4 satellite data, we examine activities of fast magnetosonic (MS) waves in the outer radiation belt near the location L=4.2 on 28 May 2005. We adopt a Gaussian distribution to fit the observed power spectral density of MS waves and find the fitting wave strength to be 245 pT. We then calculate the bounce-averaged diffusion coefficients and show that these diffusion coefficients are pronounced within a region of pitch angles about 25°–70°. By solving a 2D Fokker-Planck diffusion equation, we simulate the dynamic evolution of the electron phase space density (PSD), and demonstrate that significant increases in electron PSDs at energies of MeVs occur mainly within the aforementioned pitch-angle range over a time scale of several hours. The current results suggest that the interaction between MS waves and electrons could be an important mechanism of electron acceleration in the radiation belt.     

Fred’s Flow (Canada) and Murphy Well (Australia): thick komatiitic lava flows with contrasting compositions,emplacement mechanisms and water contents

Two Archaean komatiitic flows, Fred’s Flow in Canada and the Murphy Well Flow in Australia, have similar thicknesses (120 and 160 m) but very different compositions and internal structures. Their contrasting differentiation profiles are keys to determine the cooling and crystallization mechanisms that operated during the eruption of Archaean ultramafic lavas. Fred’s Flow is the type example of a thick komatiitic basalt flow. It is strongly differentiated and consists of a succession of layers with contrasting textures and compositions. The layering is readily explained by the accumulation of olivine and pyroxene in a lower cumulate layer and by evolution of the liquid composition during downward growth of spinifex-textured rocks within the upper crust. The magmas that erupted to form Fred’s Flow had variable compositions, ranging from 12 to 20 wt% MgO, and phenocryst contents from 0 to 20 vol%. The flow was emplaced by two pulses. A first ~20-m-thick pulse was followed by another more voluminous but less magnesian pulse that inflated the flow to its present 120 m thickness. Following the second pulse, the flow crystallized in a closed system and differentiated into cumulates containing 30–38 wt% MgO and a residual gabbroic layer with only 6 wt% MgO. The Murphy Well Flow, in contrast, has a remarkably uniform composition throughout. It comprises a 20-m-thick upper layer of fine-grained dendritic olivine and 2–5 vol% amygdales, a 110–120 m intermediate layer of olivine porphyry and a 20–30 m basal layer of olivine orthocumulate. Throughout the flow, MgO contents vary little, from only 30 to 33 wt%, except for the slightly more magnesian basal layer (38–40 wt%). The uniform composition of the flow and dendritic olivine habits in the upper 20 m point to rapid cooling of a highly magnesian liquid with a composition like that of the bulk of the flow. Under equilibrium conditions, this liquid should have crystallized olivine with the composition Fo94.9, but the most magnesian composition measured by electron microprobe in samples from the flow is Fo92.9. To explain these features, we propose that the parental liquid contained around 32 wt% MgO and 3 wt% H₂O. This liquid degassed during the eruption, creating a supercooled liquid that solidified quickly and crystallized olivine with non-equilibrium textures and compositions.