The deposit size frequency method for estimating undiscovered uranium deposits

The deposit size frequency (DSF) method has been developed as a generalization of the method that was used in the National Uranium Resource Evaluation (NURE) program to estimate the uranium endowment of the United States. The DSF method overcomes difficulties encountered during the NURE program when geologists were asked to provide subjective estimates of (1) the endowed fraction of an area judged favorable (factorF) for the occurrence of undiscovered uranium deposits and (2) the tons of endowed rock per unit area (factorT) within the endowed fraction of the favorable area. Because the magnitudes of factorsF andT were unfamiliar to nearly all of the geologists, most geologists responded by estimating the number of undiscovered deposits likely to occur within the favorable area and the average size of these deposits. The DSF method combines factorsF andT into a single factor (F·T) that represents the tons of endowed rock per unit area of the undiscovered deposits within the favorable area. FactorF·T, provided by the geologist, is the estimated number of undiscovered deposits per unit area in each of a number of specified deposit-size classes. The number of deposit-size classes and the size interval of each class are based on the data collected from the deposits in known (control) areas. The DSF method affords greater latitude in making subjective estimates than the NURE method and emphasizes more of the everyday experience of exploration geologists. Using the DSF method, new assessments have been made for the young, organic-rich surficial uranium deposits in Washington and idaho and for the solution-collapse breccia pipe uranium deposits in the Grand Canyon region in Arizona and adjacent Utah.     

新地球观

One of the most important achivements on science in 20th century is the new recognition on the Earth:the Earth,out of the other planets, exhibits very peculiar features because it has an extremely complex and active periphery part (surfacial layers). This periphery part is an open system sustained by inputting solar energe , which is captured , transfered and stored by life. Through the system , cyclings of matters and energe flow are driven and regulated by life activities. This system is self-equilibrated,self-controlled and far away from astrophysical and thermodynamic equilibria mainly because of life and life activities.
Development of human calture influences increasingly on流Earth's periphery system , at last , the natural biosphere that has existed for 3 billion years on the Earth's surface will inavoidably be replaced by so called "noosphere",which is man一reconstructed,man-controlled and unstable system. Thus the fate of the Earth,to a great extent,will be determined by the direction of human calture evolution.
     

新疆第三次荒漠化监测中的问题及其建议

回顾了新疆3次在荒漠化监测中所进行的荒漠化监测与评价指标体系的建立，也是新疆开展荒漠化监测的基础；介绍了以遥感与地理信息为主要技术的荒漠化监测评价的方法；阐述了新疆第三次荒漠化监测中存在的问题。指出目前新疆荒漠化评价存在的主要问题是评价指标的不确定性、评价指标体系的难操作性和遥感数据源选用的随机性，进而对上述问题的解决途径进行了讨论。     

The impact of residential desegregation on social integration: Evidence from a South African neighbourhood

This paper analyses the potential for social integration in post-apartheid urban South Africa by examining the lives of those already living in desegregated spaces. The case study is a low-cost state-assisted housing project situated in the wealthy southern suburbs of Cape Town. In this social housing project, named Westlake village, coloured and Black African (alongside a handful of white and Indian) residents were awarded state housing in 1999 as replacement for their previous homes (informal and formal), which were demolished to make way for a mixed land-use development, of which their new homes form a small component. Westlake’s desegregation is found to extend beyond mere residential abode, affecting resident’s everyday lives to the extent that apartheid’s history and geography are superseded by other factors (such as proximity and affordability) in decision-making. Furthermore, integration at the everyday level of informal neighbourly mixing is prevalent. Although more formal cross-race friendships are rare, discussion reveals this as a consequence of Westlake’s specific socio-historic identity rather than racial divisions per se. Empirical evidence is used to propose a continuum of social integration experience. This continuum addresses the form of integration, for example greeting in the street, visiting homes, inter-marriage; and also the spaces of integration, for example physical space (shared neighbourhood), economic space (common employment-type), social space (cross-race friendship), political space (common involvement in civic organisations) and cultural space (shared sense of belonging).     

Carbon, sulfur and O2 across the Permian–Triassic boundary

A model for the carbon and sulfur cycles across the Permian–Triassic boundary has been constructed from carbon and sulfur isotopic data. Results indicate a drop in global organic matter burial, the formation of an anoxic deep ocean, and a large drop in atmospheric oxygen over the time span 270 to 240 Ma. Much of these changes were probably due to a drop in terrestrial productivity and preservation and an increase in global aridity.     

Forests, climate, and silicate rock weathering

Over time periods of 10⁶ years and longer, atmospheric carbon dioxide content is largely controlled by a balance between silicate rock weathering and CO₂ sources (degassing from the Earth plus net organic carbon oxidation). Vegetation cover can affect silicate rock weathering rates by increasing soil CO₂ content, stabilizing soil cover, and producing organic acids. Forests absorb more solar radiation than most other ecosystems; this tends to warm Earth's climate, especially outside of the tropics; this warmth would tend to increase silicate rock weathering rates. Here, we develop preliminary parameterizations of this effect that could be incorporated into carbonate–silicate cycle models, based on the results of general circulation model simulations.     

Spatial analysis of elements in soils from Chengdu City

Three kinds of spatial analysis methods （geostatistics, concentration-area fractal model and the multifractal analysis called the moment method） were used for almost 50 elements, including heavy metals, disperse elements, rare elements and even others, in 6586 top soil （0-20 cm） samples and 1833 deep soil （150-200 cm） samples from Chengdu metropolitan area of 12400 km^2, southwestern China. The ranges of spatial correlation revealed by variograms are quite different for different kinds of elements in the top and deep soils. The most interest is the fact that the multifractal spectra of environmentally important elements such as Pb, Cr, Cd and Ni in top soils in the metropolitan area show systematic change from those in the deep soils, revealing a strong anthropogenic addition, while Hg, Zn, As, Cu and all common elements show no such kind of addition. In terms of multifractal properties based on the multifractal spectrum curves, those disperse and rare elements show great deviation from other major and trace elements, which is also of great interest.     

Measurement of the total nitrogen in lake sediments： Comparison and its environmental significance

Nitrogen cycle is an important bio-geochemical process in the environment. Measurement of the total nitrogen （TN） is a routine experiment in agriculture, biology and environmental sciences. The Kjeldahl method （KM） and elemental analyzer method （EA） are both commonly used to determine TN. Total nitrogen by EA is the sum of nitrate （NO3）, nitrite （NO2）, organic nitrogen and ammonia. Total nitrogen by KM （TKN） is made up of both organic nitrogen and ammonia. A comparative study focused on the two methods is conducted by analysis of TN in 97 samples from the sediment sequence of Gouchi, a salt lake in North China. KM presents a higher degree of accuracy than EA with a standard deviation of 0.007 vs. 0.024. With the presence of nitrate and/or nitrite nitrogen, however, measurement by KM is considerably lower than that by EA. Therefore, for samples from lake sediment sequences or soils in North China, KM is inapplicable to determining TN because of usually high contents of nitrous salt. Despite the inconsistency, use of both methods to the same samples makes sense in reconstructions of climatic and environmental changes from lake sediments. In Lake Gouchi, the contents of nitrate and nitrite nitrogen vary from 1.40% in the lower part of the sequence to 14.77% in the uppermost part, suggesting a gradual evolution process from a fresh water lake to the present-day salt lake.