Factors affecting the elimination of PCBs in the marine copepod Acartia tonsa

The effects of feeding, egg laying, and fecal pellet production on the elimination of polychlorinated biphenyls (PCBs) from the marine copepod Acartia tonsa were studied in a series of experiments. Copepods were exposed to ¹⁴C-labelled Aroclor 1254 and allowed to depurate in clean seawater. Copepods fed during depuration eliminated PCBs more rapidly than unfed copepods whether or not the original PCB exposure medium had contained food. Both eggs and fecal pellets contained PCBs during depuration, with the weight specific concentration of PCB in the eggs (up to 407 ppm, dry weight) exceeding four times that in the females that produced them. Female copepods eliminated PCBs twice as rapidly as males, indicating that egg production is an important route for PCB elimination.     

云南天文台1m望远镜暗天体分光仪和照相机

云南天文台1m望远镜终端之一的暗天体分光仪和照相机具有4种运行模式:缩焦照相机、无缝多目标光谱仪、有缝光谱仪和星冕仪。这4种运行模式能在几分钟的时间内相互转换,高效快速和灵活方便。该仪器的光学质量优秀,光学系统消像差,特别是消色差。由于光学系统消色差,所成像的低色散光谱在404.6～766.5nm全波段尖锐平直。在多色测光时,各测光波段的像面位置不变,同时兼有大视场的优点,可提高测光精度和测光效率。     

Provenance of Palaeozoic sandstones from the Carnic Alps (Austria): petrographic and geochemical indicators

An integrated approach of petrographic analysis, whole rock geochemistry and microprobe analysis has been applied to obtain information on the geodynamic development and the provenance for Ordovician to Permian siliciclastic successions exposed within the Carnic Alps (Austria). Sandstone detrital mode and geochemical results refine previous geodynamic interpretations. Late Ordovician samples indicate a stable craton and recycled orogenic and, possible, extensional setting. The Early Carboniferous is interpreted to represent a compressional environment, followed by a Late Carboniferous molasse-type foreland basin, and a Permian extensional geodynamic setting. Contrasting geochemical patterns of post-Variscan and Permian sequences suggest a rift setting. Electron microprobe data of detrital white mica also indicate changes in the provenance. Compositional data reflect a shift from low- to medium-grade metamorphic (Ordovician) to high-grade metamorphic (Carboniferous) to low- to medium-grade metamorphic and plutonic source rocks (Permian). Additionally, our data show that various chemical discrimination diagrams do not include all possible ranges of sandstones, and that high contents of detrital mica and ultra-stable heavy minerals may cause misclassification. Consequently, we propose the use of multi-method approach for provenance studies, including the control of geochemical data by modal analysis and heavy mineral investigations.     

基于空间统计分析与GIS的人均GDP空间分布模式研究

本文将空间统计分析与G IS相结合,探讨我国地级及以上城市人均GDP在空间分布上的特征。研究表明,我国地级及以上城市人均GDP在整体上呈现显著的空间集聚性,而在东、中、西部三个区域呈现不同的空间关联模式。     

淮河流域5～6月降水的年际及年代际变化

对淮河流域降水异常进行分析对于预测黄海绿潮具有重要意义。选取淮河流域10个站,长江流域15个站,通过对国家气象信息中心1951~2011年的逐月降水数据进行分析,研究淮河流域和长江流域5~6月平均降水异常。2000~2010年,淮河流域5~6月降水呈现增加趋势,与长江流域降水呈反位相变化。分别对淮河流域5~6月平均降水异常与印度洋偶极子指数(Dipole Mode Index,DMI),以及太平洋年代际振荡(the Pacific Decadal Oscillation,PDO)指数做相关性分析,结果表明:淮河流域5~6月平均降水异常与6个月前的DMI指数达到最大正相关,与20个月前的北太平洋(20°N以北)SST呈现明显的负相关,与PDO指数达到最大负相关。这表明,PDO、DMI指数对淮河流域5~6月降水异常的年代际、年际变化具有明显的指示作用。     

GZCORS在广州轨道交通水下地形测量中的应用

水下地形图是轨道交通工程规划、设计、施工的重要基础资料,本文以广州轨道交通三号线流溪河水下地形测量为例,阐述了广州市连续运行参考站城市3维定位系统(GZCORS)在水下地形测量中的作业模式、方法及精度。该种作业模式在河道、沿海港口等水下地形测量中有着广阔的应用前景。     

青海湖流域草地产草量与MODIS植被指数的相关性分析

借鉴国内外基于遥感手段监测植被的方法,利用MODIS-NDVI遥感影像数据,探讨如何对草地变化进行监测。提取青海湖流域典型草原遥感影像植被指数,并与野外调查获得的79个样方生物量数据进行对比分析,建立了多个回归模型用于研究植被指数与草地产草量的相关关系。结果表明,植被指数与草地产草量之间存在较好的相关性,但是不同的回归模型与草地产草量相关性程度存在一定的差别,非线性回归模型优于一元线性回归模型,该方法的提出有助于监测青海湖流域草地变化情况。     

参考经验模态分解-独立分量分析及其在GPS多路径误差处理中的应用

多路径误差在绝大部分应用中,其测站间相关性很弱,不能通过差分观测得到有效削弱,成为高精度GPS动态变形监测中的主要误差源。针对GPS多路径误差的特点,结合具有良好多尺度分解能力的经验模式分解方法(EMD)和具有良好盲分离能力的独立分量分析(ICA)方法,提出带参考信号的EMD-ICA方法来削弱多路径效应的影响。应用实例的结果证明了该方法的有效性。