Clustering Property of Wolf-Rayet Galaxies in the SDSS

We have analysed, for the first time, the clustering properties of Wolf-Rayet (W-R) galaxies, using a large sample of 846 W-R galaxies selected from the Data Release 4 (DR4) of the Sloan Digital Sky Survey (SDSS). We compute the cross-correlation function between W- R galaxies and a reference sample of galaxies drawn from the DR4. We compare the function to the results for control samples of non-W-R star-forming galaxies that are matched closely in redshift, luminosity, concentration, 4000-A break strength and specific star formation rate (SSFR). On scales larger than a few Mpc, W-R galaxies have almost the same clustering amplitude as the control samples, indicating that W-R galaxies and non-W-R control galax- ies populate dark matter haloes of similar masses. On scales between 0.1-1 h-1 Mpc, W-R galaxies are less clustered than the control samples, and the size of the difference depends on the SSFR. Based on both observational and theoretical considerations, we speculate that this negative bias can be interpreted by W-R galaxies residing preferentially at the centers of their dark matter haloes. We examine the distribution of W-R galaxies more closely using the SDSS galaxy group catalogue of Yang et al., and find that ～82% of our W-R galaxies are the central galaxies of groups, compared to ～74% for the corresponding control galaxies. We find that W-R galaxies are hosted, on average, by dark matter haloes of masses of 1012,3 M☉, compared to 1012,1 M? For centrally-located W-R galaxies and 1012,7 M☉ For satellite ones. We would like to point out that this finding, which provides a direct observational support to our conjecture, is really very crude due to the small number of W-R galaxies and the incom- pleteness of the group catalogue, and needs more work in future with larger samples.     

Heavy Metal Concentrations in the Intertidal Gastropod Nerita lineata and Their Relationships to Those in Its Habitats： A Case Study in Dumai Coastal Waters

Concentrations of heavy metals in the intertidal gastropod Nerita lineata collected from 4 sampling stations in the intertidal zone of Dumai coastal waters have been analyzed and correlated with the respective metal concentrations in their habitat. The objective of this study was to evaluate the possible relationships between heavy metal concentrations in the N.lineata with metal concentrations in their habitat, which include seawater, algal mat, suspended particulate matter, and surface sediment. The results showed that heavy metal concentrations in the sediment, N.lineata, suspended particulate matter, algal mat and surface seawater were found to be higher in stations closed to Dumai city center which has more industrial and anthropogenic activities. The mean concentrations of Cd, Cu, Pb, Zn, Ni and Fe in the N.lineata collected from Dumai intertidal area were 4.14 μg/g, 5.90 μg/g, 44.43 μg/g, 3.74 μg/g, 20.73 μg/g, 24.91 μg/g in shell; 4.16 μg/g, 7.31 μg/g, 51.78 μg/g, 17.63 μg/g, 23.52 μg/g, 30.60 μg/g in operculum and 0.71 μg/g, 15.09 μg/g, 9.41 μg/g, 94.42 μg/g, 5.10 μg/g, 398.24 μg/g dry weight in the total soft tissue, respectively. Cd, Pb and Ni concentrations of parts of the N.lineata were in the order: that of operculum>shell>soft tissue whilst Cu, Zn and Fe concentrations of parts of the N.lineata in the order: that of soft tissue>operculum>shell. This suggested that N.lineata could be used as biomonitoring agent for Cu, Zn and Fe (soft tissues) and for Cd, Pb and Ni (operculum). However, the shell had significant correlations (P<0.05) with metal concentrations in the sediment, algal mat, suspended particulate matter and seawater. Bioconcentration factor (BCF) values of the shell also revealed greater capacity for non-essential metals bioaccumulation from all environmental phases. This might suggest that the shell of N.lineata could be better used as biomonitoring agent for heavy metal pollution.     

Simultaneous core sample measurements of elastic properties and resistivity at reservoir conditions employing a modified triaxial cell – a feasibility study

Adaptations of existing triaxial cells for ultrasonic P- and S-wave measurements are well documented. This paper proposes further modification of such a cell so that also resistivity measurements can be carried out simultaneously at reservoir conditions. By employing the top cap and the pedestal of the cell as electrodes, axial resistivity measurements are now feasible. In order to minimize the polarization effect of this two-electrode arrangement, careful analyses have been carried out to optimize the choice of electrode coating and measurement frequency band. Radial resistivity measurements are also included in the system by introducing a strap-electrode system.
In a reservoir under production changes in both saturations, temperature (if steam injection) and stresses can take place. Therefore the modified triaxial system should be able to measure the integrated effects on the acoustic parameters and electric responses caused by variations in each of these parameters. The feasibility of the system to obtain such reliable information is demonstrated, employing a small selection of core samples. In the future such combined measurements on reservoir core samples can be used to link both seismic and electromagnetic observations to the actual earth model and constrain both modelling and inversion.     

利用接收函数研究延边地震台下方地壳结构

收集整理2007年以来延边地震台记录的113个远震数字波形资料,采用远震接收函数反演延边地震台下方地壳结构,运用H-Kappa叠加方法,计算得到台站下方地壳厚度和泊松比.采用全球平均地壳模型作为初始模型,反演台站下方0-100 km的S波速结构.反演结果表明,延边地震台下方地壳厚度为30.8 km,波速比为1.84,泊松比较高,为0.29.在台站下方15-20 km及25-30 km处存在低速层.     

Thyroid cancer incidence in China between 2005 and 2009

Thyroid cancer (TC) incidence has significantly increased worldwide in recent decades, with large differences between urban and rural areas. However, studies on Chinese TC incidence are limited. Research on the relationship between TC incidence and industry activities is also rare. In this work, data from 31 cancer registry cities in China between 2005 and 2009 were used to reveal the trend of TC incidence, compare the incidence among different cities, and analyze the relationship of TC incidence with socioeconomic factors. During the five-year period, TC incidence in China increased by 49.5 % from 3.21/100,000 to 4.80/100,000, with a female–male ratio of 3 and an urban–rural ratio of 2.5. The increase of TC incidence in more developed cities was significant, but it was not in less developed cities. People living in cities with higher secondary industry output had a higher risk of developing TC. The government and scientific community should pay sufficient attention to the rapidly increasing incidence of TC and to industry activities.     

Cosmogenic nuclide burial age of the Sanying Formation and its implications

The Pliocene fluvial/lacustrine sediments of the Sanying Formation lie along the Red River fault and its northwest extension;their majority outcrops appear around Eryuan.The Sanying Formation is characterized by multiple intercalated coal layers and its unconformities contact with the underlying Triassic limestone and the overlying Quaternary coarse sediments.Cosmogenic nuclide burial dating confirms the Pliocene age of the Sanying Formation.The burial ages of the overlying Quaternary sediments provide the lower age limit of the Sanying Formation:2 Ma.Detrital zircon U-Pb age distribution suggests provenance of the Sanying Formation traced to the Songpan-Ganzi flysch belt.From the spatial distribution as well as sedimentary and fault ages,we found a strong connection of the Sanying Formation with the Red River and the Jianchuan faults.We therefore propose that activation of the Red River and the Jianchuan faults during the Late Miocene resulted in subsidence of basins in the extensional areas around Eryuan and in the middle to south segments of the Red River fault.The basins were filled with water carried by the Jinsha River and overflow-lakes formed within the basins where the Sanying Formation was deposited.Most of the lakes were dried and sedimentation of the Sanying Formation ceased due to the uplift of the Yunling Mountains,which forced rerouting of the Jinsha River at the beginning of Quaternary.     

The role of land use on the local climate and air quality during calm inter-monsoon in a tropical city

The modification of land use is known to be a major climate change driver to the local warming and air quality in cities. Despite the reduction of NOx over the years, the Selangor state has captured a higher level of O_3 in year 2011. The measurement result has shown that the surge in O_3 level was attributed to the reduction of NO_x/NMHC ratio. This paper hence attempted to identify the role of land use change from 1999 to 2011 on the ground ozone air quality in the tropical urban conurbation, Greater Kuala Lumpur(GKL), Selangor, Malaysia. With the state-of-the-art chemical weather prediction tool, WRFChem, the external synoptic factors and emission inventory were controlled when comparing the chronological land use changes. The results showed that the urban-induced temperature and wind bias in the tropical region has induced stronger wind to disperse the NO_x and carries the TVOC from the suburban to the downwind urban region. The reduction of NO_x/TVOC has gradually shifted towards the optimum O_3 formation regime in 2011. The formation of highly concentrated ozone becomes more sensitive to the increment of TVOC as the NO_x level reduces in the urban. This highlights the essential involvement of TVOC in the ozone formation in lieu of the NOx reduction in the tropical city, a region with growing emitter of reactive biogenic ozone precursors.     

A simplified design method for energy piles

This paper introduces a simplified method to investigate the influence of thermal loads on the shaft friction and tip resistance of energy piles. The method is based on the influence factors (λ and η) which are back-calculated drawing on a large number of field and model tests. Values for λ and η during heating and cooling are suggested. Moreover, a new equation is proposed to calculate total shaft friction. The equations concerning the relationship between η and temperature difference are recommended to investigate the impacts of the thermal load on the pile tip resistance. The slope of the linear equation of an end-bearing pile is 2.14 times that of a floating pile indicating that the pile tip resistance of an end-bearing pile is much more affected by the same thermal load.

     

四川攀枝花昔格达组及其下伏河流砾石的地球化学特征以及对物源的制约

位于扬子地块西缘的攀枝花地区昔格达组湖相沉积及其下伏河流相砾石比较发育。湖相沉积具有较高的SiO2含量和Al2O3/SiO2比值,显示其载体沉积物具有较高成熟度,表明经历了长距离的搬运。主元素、稀土(REE)和微量元素分析结果揭示昔格达组湖相沉积物源形成于典型的大陆岛弧构造背景,主要来自松潘-甘孜造山带义敦岛弧花岗岩区。Eu/La?Yb/La判别图与Zr/Y比值进一步证实昔格达组湖相沉积分别来自于金沙江上游及雅砻江上游,说明昔格达古湖形成时金沙江上游已被袭夺。昔格达组下伏河流相砾石REE、微量元素分析结果显示其形成于被动大陆边缘构造背景,说明其是由雅砻江经扬子板块边缘花岗岩区携载而来。昔格达组湖相沉积与其下伏河流相砾石的不同物源特征表明伴随着昔格达古湖的形成,金沙江河流经历了演化史上的巨变。     

东昆仑扎玛休玛正长花岗岩年代学、地球化学特征及其构造意义

东昆仑出露大面积的中酸性侵入岩,为研究大陆地壳生长提供了天然实验室。该区古特斯时期花岗岩形成的构造背景及其深部演化过程一直存在争议,本文通过对东昆仑扎玛休玛地区出露的正长花岗岩开展岩相学、锆石U-Pb定年、Hf同位素及地球化学研究,以期限定其形成时代,探讨岩石成因,为解决上述问题提供新依据。正长花岗岩由斜长石,碱性长石,石英,黑云母,少量角闪石等组成,LA-ICP-MS锆石U-Pb年龄为240.3±1.8Ma,形成于中三叠世;岩石地球化学结果富硅(SiO_2=70.36%～71.20%),相对富碱,Na_2O+K_2O含量为7.52%～7.89%,Al_2O_3含量为14.06%～14.18%,TiO_2和MgO含量低,富集大离子亲石元素Rb、Th等,相对亏损Nb、Ta、Ti等高场强元素特征,岩石属于高钾钙碱性准铝质-弱过铝质Ⅰ型花岗岩;ε_(Hf)(t)值介于-4.1到+2.3之间,二阶段Hf模式年龄T_(DM2)为1126～1536 Ma,暗示正长花岗岩源于中元古古老地壳熔融。综合分析认为扎玛休玛正长花岗岩形成于活动大陆边缘环境,是东昆仑古特提斯洋由俯冲向碰撞转换阶段的产物。