地理现象的可分割性质

在过去几年里,分割的概念引起了人们的极大关注。其主要思想起源于地图数据研究,而且它的很多应用继续牵涉到空间现象。在对比例尺的答复、自相似和空间循环细分三个标题下,我们回顾了地理学与分割的关联。分割度大小为表现制图综合效果特性和评价以空间样本为预告对象所推出的数据表示提供了手段。分割表面自相似特性,使得它如同在地貌过程研究中开始的或不存在的假设景观一样有用。空间现象的广泛变化,据统计,在许多规模上被证明是自相似,使人想起了像地理范围那样的比例尺依存关系的重要性。在文章三分之一的篇幅里,循环细分被证明是导致用数字形式表示空间数据的新奇和有效方法,并成为空间组织常见模型的特征。我们断定,分割被作为考虑空间形式传统方法重要变化,同时,与其说是提供了空间现象新的和重要的规范与标准,倒不如说提供了以经验为根据的可证实模型。     

A 2D finite volume model for bebris flow and its application to events occurred in the Eastern Pyrenees

FLATModel is a 2D finite volume code that contains several original approaches to improve debris-flow simulation. Firstly, FLATModel incorporates a ＂stop-and-go＂ technique in each cell to allow continuous collapses and remobilizations of the debris-flow mass. Secondly, flow velocity and consequently yield stress is directly associated with the type of rheology to improve boundary accuracy. Thirdly, a simple approach for entrainment is also included in the model to analyse the effect of basal erosion of debris flows. FLATMODEL was tested at several events that occurred in the Eastern Pyrenees and simulation results indicated that the model can represent rather well the different characteristics observed in the field.     

根据红外光谱分析和分子轨道计算结构建立的钠长石熔体中水溶解机…

Ｈ２Ｏ－和Ｄ２Ｏ－ＮａＡｌＳｉ３Ｏ２玻璃的红外光谱与无水钠长石玻璃的红外光谱之间有两大差别：一量有许多由数个Ｏ－Ｈ伸缩振动引起的高于３０００ｃｍ＾－１的谱带出现，二是在含水玻璃红外光谱中的９００ｃｍ＾－１附近出现一个谱肩。未发现因Ｄ－Ｈ置换而引起的９００ｃｍ＾－１谱肩的频率偏移。根据我们的红外光谱和分子轨道计算结果，以及以前的ＮＭＲ和喇曼光谱，我们得出结论：Ｈ２Ｏ－钠长石玻璃的振动光谱中９００ｃｍ     

Marine risk assessment: linear alkylbenzenesulponates (LAS) in the North Sea

The fate of linear alkylbenzenesulponates (LAS) in estuaries and coastal areas of the North Sea has been characterized with simple environmental models. The predicted concentration range in the estuaries around the North Sea (0.9-9 microg LAS l(-1)) was validated by monitoring data (1-9 microg LAS l(-1)). In offshore sites of the North Sea, it is estimated--and experimentally verified for a few sites--that the LAS concentration is below analytical detection limit (i.e., 0.5 microg LAS l(-1)). The effects of LAS on marine organisms have been reviewed. For short-term acute tests, there was no significant difference (p = 0.83) between the mean LC50 values of freshwater and marine organisms (mainly pelagic species tested, 4.1 and 4.3 mg LAS l(-1), respectively). For longer-term chronic tests, it appeared that the sensitivity (mean no-observed effect concentration (NOEC) value) of marine and freshwater organisms (0.3 and 2.3 mg LAS l(-1), respectively) was significantly different pt-test = 0.007). The predicted no-effect-concentrations (PNEC) were 360 and 31 microg LAS l(-1), for freshwater and marine pelagic communities, respectively. Given that the maximum expected estuarine and marine concentrations are 3 to > 30 times lower than the PNEC, the risk of LAS to pelagic organisms in these environments is judged to be low.     

Analyses of organic and inorganic contaminants in Salton Sea fish

Chemical contamination of fish from the Salton Sea, a quasi-marine lake in Southern California, could adversely impact millions of birds using the Pacific Flyway and thousands of humans using the lake for recreation. Bairdiella icistia (bairdiella), Cynoscion xanthulus (orangemouth corvina), and Oreochromis spp. (tilapia) were sampled from two river mouths and two nearshore areas of the Salton Sea. Muscle tissues were analyzed for a complete suite of 14 trace metals and 53 pesticides. Fish muscle tissues had concentrations of selenium ranging between 1.89 and 2.73 microg/g wet weight. 4,4'-DDE accounted for 94% of the total DDT metabolites. Total DDTs ranged between 17.1 and 239.0 and total PCBs between 2.5 and 18.6 ng/g wet weight. PCB congeners 132, 138, 153, 168, and 180 comprised over 50% of the total PCBs. Given the potential implementation of a commercial fishing at the Salton Sea in the future, the presence of persistent organic pollutants and selenium warrants further research into the effects of these mixtures on fish populations, and on wildlife and humans consuming fish.     

圣安德烈斯断层的强度

在过去25年里,对沿加利福尼亚州的圣安德烈斯断层系的运动速率和长期地震记录的认识已显著提高了。这些认识使得对地震发生概率,尤其是30年周期概率的长期估计成为可能(Working Group on California Earthquake Probabilities,1999)。但是,我们对断裂产生的物理过程的了解仍然非常不足——关于短期预报的可行性问题、一个断层产生地震是否会增加另一断层     

A database of archived drilling records of the drill cuttings piles at the North West Hutton oil platform

Drill cuttings piles are found underneath several hundred oil platforms in the North Sea, and are contaminated with hydrocarbons and chemical products. This study characterised the environmental risk posed by the cuttings pile at the North West Hutton (NWH) oil platform. Data on the drilling fluids and chemical products used over the platform's drilling history were transferred from archived well reports into a custom database, to which were added toxicological and safety data. Although the database contained many gaps, it established that only seven chemical products used at NWH were not in the lowest category of the Offshore Chemicals Notification Scheme, and were used in only small quantities. The study therefore supports the view that the main environmental risk posed by cuttings piles comes from hydrocarbon contamination. The (dated) well records could help future core sampling to be targeted at specific locations in the cuttings piles. Data from many platforms could also be pooled to determine generic 'discharge profiles.' Future study would benefit from the existence, in the public domain, of a standardised, 'legacy' database of chemical products.     

STRUCTURE AND COMPOSITION OF A WATERSHED-SCALE SEDIMENT INFORMATION NETWORK

A "Watershed-Scale Sediment Information Network" (WaSSIN), designed to complement UNESCO’s International Sedimentation Initiative, was endorsed as an initial project by the World Association for Sedimentation and Erosion Research. WaSSIN is to address global fluvial-sediment information needs through a network approach based on consistent protocols for the collection, analysis, and storage of fluvial-sediment and ancillary information at smaller spatial scales than those of the International Sedimentation Initiative. As a second step of implementation, it is proposed herein that the WaSSIN have a general structure of two components, (1) monitoring and data acquisition and (2) research. Monitoring is to be conducted in small watersheds, each of which has an established database for discharge of water and suspended sediment and possibly for bed load, bed material, and bed topography. Ideally, documented protocols have been used for collecting, analyzing, storing, and sharing the derivative data. The research component is to continue the collection and interpretation of data, to compare those data among candidate watersheds, and to determine gradients of fluxes and processes among the selected watersheds. To define gradients and evaluate processes, the initial watersheds will have several common attributes. Watersheds of the first group will be: (1) six to ten in number, (2) less than 1000 km2 in area, (3) generally in mid-latitudes of continents, and (4) of semiarid climate. Potential candidate watersheds presently include the Weany Creek Basin, northeastern Australia, the Zhi Fanggou catchment, northern China, the Eshtemoa Watershed, southern Israel, the Metsemotlhaba River Basin, Botswana, the Aiuaba Experimental Basin, Brazil, and the Walnut Gulch Experimental Watershed, southwestern United States.     

First record of dinosaur trackway from Tibet,China

Three sauropod trackways comprise eight tracks that resemble Brontopodus tracks have been found at the Morong track site in Changdu Prefecture, Tibet, China. These wide- (or sub-wide)-gauge tracks suggest that there was a large sauropod, possibly a member of Titanosauriformes, in Changdu Prefecture during the Early-Middle Jurassic. The sauropod fauna from Changdu Prefecture, Tibet not only has elements in common with the sauropod fauna from the Sichuan Basin, but may include more diverse faunal components.