People’s perception and socioeconomic determinants of soil erosion:A case study of Samanalawewa watershed,Sri Lanka

Though soil erosion is an important concern in Sri Lanka, there is a dearth of baseline information on soil erosion in many ofits watersheds, which obstructs monitoring of soil erosion and mitigating its effects. In order to assess soil erosion in a critical watershed and to identify its determinants, the Samanalawewa watershed, which contains one of the main hydropower generating reservoirs in Sri Lanka, was selected for this study. Remote-sensing (RS) and geographic information system (GIS) based modeling...     

山东莒南后左山恐龙公园早白垩世恐龙足迹化石初步研究

山东省莒南县后左山恐龙公园内保存了数量众多、形态各异的恐龙足迹化石。该足迹化石群产于早白垩世大盛群田家楼组,主要是兽脚类、鸟脚类恐龙的足迹,尤以前者占优质。最大的一个为椭圆形,大小100cm×70cm,可能系鸟脚类恐龙的足迹。鸟脚类足迹大多为椭圆形,长轴一般30～40cm,常呈幻迹保存。最大的兽脚类足迹为三趾型,长49cm,宽35cm,是大型肉食龙类的足迹;最小的一个长8.5cm,宽4.5cm,可能是虚骨龙类的足迹。另外还发现了少量可能是驰龙的足迹,具有2个很长的趾(Ⅲ和Ⅳ趾),趾间角极小,二者几乎平行。鸟脚类恐龙足迹层位分布局限,但密度较大,产出的层面常发育泥裂、波痕,甚至冰晶痕,与泥岩、粉砂质泥岩等层位相关性较强。     

Puziwan Gold Deposit in Shanxi, China: A Special Linear Cryptoexplosive Breccia Type Gold Deposit

The Puziwan gold deposit is a special linear cryptoexplosive breccia type deposit found in northeastern Shanxi, China, in recent years. The deposit is located in a secondary metallogenic. belt of the most famous Au-Ag polymetallic metallogenic belt along the north margin of the North China platform. The secondary metallogenic belt is a synmagmatic tension-shear fault-fracture belt of ENE linear trend. The Indosinian cryptoexplosive breccia body, quartz monzonitic porphyry (beschtauite breccia), quartz monzonite (243.7 Ma, K-Ar), Yanshanian granite-porphyry (105±6 Ma, Rb-Sr) and orebodies mostly occur as dykes or veins and short lenses along the structural fracture belt. The orebodies are emplaced in the fractured cryptoexplosive breccia body in the tectonomagmatic belt and their attitude is consistent with that of the breccia body. The orebodies have two types: one is shallow-seated thick and big ones, which are short-lenticular in plan and wedge-shaped in cross section, shallow buried, large in size a     

Sedimentary Features and Sea-Level Changes Reflected in Drill Holes in the Zhuhai Area

Experimental examinations and analyses have been made of the sediments from drill holes in the Zhuhai area, Guangdong Province. The studies show that there occurred four transgressions in this area over the historical times. The first transgression occurred at 7500 a B.P., with the maxium sea level up to about 1 m above the present level. The second transgression occurred at 5750 a B.P., with the sea level possibly 4 m higher than the present. The third and fourth transgressions took place at 4650 a B.P. and 2600 a B.P. respectively, which lasted for a long time with multiple fluctuations. The fifth transgression is in process. It could be predicted that the sea level at Zhuhai would rise by 15-20 cm in the coming 50 years.     

Stream Function Wave Derived by Unified Variational Principle of Water Gravity Wave

Based on the linear wave,solitary wave and fifth order stokes wave derived by use of the Uni-fied Variational Principle of Water Gravity Wave(UVPWGW),this paper derives stream function wavetheory by using UVPWGW.This paper will handle the Kinematic Free Surface Boundary Condition(KFSBC)and Dynamic Free Surface Boundary Condition(DFSBC)directly and give the optimum solu-tion,instead of the conditions ∑(Q_(av)-Q_i)~2=min,and the related equations of stational condition.When the wave height H,period T and water depth D are given,the original stream function wave willbe determined,and can not be adjusted if it does not agree with the real case;in the present method,the ad-justment can be done by adding several constraint conditions,for example,the wave profile can be ad-justed according to the condition of accurate peak position.The examples given in this paper show that forthe original stream function wave,the DFSBC can be fairly well satisfied,but the KFSBC can not;howev-er,the stream function wave derive     

Estimation of JONSWAP Spectral Parameters by Using Measured Wave Data

- This paper presents the method of determining JONSWAP spectrum by using measured wave data. If Hs, Tz and Tc are the measured significant wave height, average zero-up crossing wave period and average period between wave crests respectively and let y = T Z / TC; this paper provides equation to solve y fromf(y,y) = 0. From the solutions of this equation and by using LSM, the expression relating y as a function of y (for 2.54相似文献   

Integrated Futures for Europe’s Mountain Regions: Reconciling Biodiversity Conservation and Human Livelihoods

Introduction Europe's mountains cover nearly half of the continent's area (Price et al. 2004) and land cover varies significantly (European Commission 2004). In most massifs, except for Sicily, southern Greece, and the British Isles, forest cover is dominant. In northern Europe, grassland is proportionately more important, and much of the mountains of the British Isles is covered by moorland. In central and southern Europe, arable land is of far greater importance than grassland, with Med…     

CLIMATIC CONTROL OF SOIL ACIDITY

A curve-fit model of the relationship between soil pH (A horizon) and climate forms the basis of a map of predicted pH for the conterminous United States. This map was produced with the aid of a large climatic data base, a computer mapping program and subroutines to map modeled values of soil pH. Patterns of pH follow well-recognized patterns of climate, although the pH of 7 line deviates greatly from Marbut's line dividing pedalfers from pedocals. The overall accuracy of the map and model was checked using a validation data set. Geographic patterns of pH are realistic, although land use, topography, and parent material may cause local variations about the predicted mean for a given region. Several apparently anamolous map patterns were also checked but found to be accurate. Prediction of the detailed pattern of pH will require variables in addition to climate.     

CLASSIFICATION:OLDTIMERS AND NEWCOMERS

Classification and regression techniques are among the most used tools by chemometricians.Withclassification,the two classic methods are discriminant analysis and SIMCA.In this paper we discuss theconnection between these two methods and introduce two new ones of the same family:DASCO(discriminantanalysis with shrunken covariances)and RDA(regularized discriminant analysis).We demonstrate on bothsimulated and real data sets that their performance is superior to the old favorites.This is especially truein small-sample/high-dimension settings typical in chemistry.     

北极楚科奇海近代沉积物稀土元素地球化学特征初探

于 1 999年夏季我国首次北极科学考察期间在楚科奇海采集了三个沉积物岩芯 ,并采用中子活化法 (INAA)测定了沉积物样品中稀土元素的含量。结果表明 ,其含量与东海大陆架细粒沉积物的稀土元素含量十分接近。稀土元素的含量沿沉积物岩心的垂直分布呈现出随深度轻微增大的趋势。页岩标准化的稀土元素配分模式相对平缓 ,Ce有轻度负异常 ,表明沉积物稀土元素除了陆源物质以外 ,也存在生物沉积作用的来源。稀土元素与指示陆源的元素Al具有良好的正相关关系 ,相对于地壳丰度所计算的富集因子接近于 1 ,进一步说明楚科奇海沉积物中的稀土元素以陆源物质输入为主 ,通过江河携带入海 ,最后随碎屑物质、悬浮物而沉积下来 ,并保持一种稳定的沉积状态。