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[en] Trends in average crop yield i.e., crop output per unit area, are the basis for numerous forecasts of the future global expanse of agriculture. Although a number of studies predict a sizable expansion in global cropland area through the year 2050, some argue, to the contrary, that peak cropland is at hand. This paper analyzes historical trends in the ‘correlation’ between annual global cropland and annual crop production using a new measure called the elasticity of cropland with respect to production (crop output). Three different statistics of elasticity—the mean, the frequency of different combinations of directional changes in crop area and output, and time trend, each computed over different but fixed time intervals (5, 10, 15 and 20 years, which were chosen arbitrarily) suggest that the global area of cropland is set to increase with consumption. Achieving an absolute reduction in global cropland hinges on increasing crop yields beyond anything seen in the last fifty years. While this is consistent with several existing forecasts, the salience of an elasticity-based analysis is that it captures the effect of changing marginal as well as average crop yield as opposed to just the latter. The elasticity-based approach is applicable to trends in the exploitation of other scarce natural resources as well as releases of different pollutants. (letter)
[en] The Altamira Supercomputer hosted at the Instituto de Fisica de Cantatbria (IFCA) entered in operation in summer 2012. Its last generation FDR Infiniband network used (for message passing) in parallel jobs, supports the connection to General Parallel File System (GPFS) servers, enabling an efficient simultaneous processing of multiple data demanding jobs. Sharing a common GPFS system and a single LDAP-based identification with the existing Grid clusters at IFCA allows CMS researchers to exploit the large instantaneous capacity of this supercomputer to execute analysis jobs. The detailed experience describing this opportunistic use for skimming and final analysis of CMS 2012 data for a specific physics channel, resulting in an order of magnitude reduction of the waiting time, is presented.
[en] The groundwater pollution in Shijiazhuang city is characterized by an excess of some components and parameters over permitted values. The main pollutants are originated from the city sewage which is quite typical for groundwater pollution in many cities of China. On the basis of agonizingly features of groundwater pollution, the relationship between the groundwater pollution and the groundwater overexploitation is discussed in this paper, and the mechanism of intensifying the pollution by overexploitation has been revealed. Finally, it is proposed that the overexploitation of groundwater is an important inducing factor leading to the groundwater pollution in cities. (authors)
[en] The bulk of the hydrocarbon encountered in the Niger Delta basin has been mostly within a depth range of 7,000ft to 12,000ft (about 2130m to 3650m) since the search for oil began in 1914. The giant finds, which are fast disappearing in the onshore Niger Delta, reside within this window. The objective of this paper is to project deep drilling as an option for exploration strategy to probe horizons below the present window, which hitherto have been left untouched due to the presence of easy-to-find alternatives.The operators, in their bid to boost the national reserves base, have over the years been encouraged to intensify their search for oil through various incentives given by the Government. This has propelled them to extend their activities to the frontier areas. It is pertinent to note that vast upside potentials lay below the present window of exploitation undiscovered because of the limitations of the existing technology of yesteryears. The story has changed. High resolution 2-D and 3-D seismic data acquisition capability with advancement in drilling technology as well as intelligent completion strategies are facilitating ingredients that should make deep drilling an attractive option.Apart from increasing the national reserves base and meeting production targets, deep drilling in the Niger Delta will reduce the operating and capital costs since only minor expansions, if nay, might be needed to upgrade the existing production facilities. Today's technological advancement has made the present time very appropriate for the operating companies to go into deep drilling as an option for sustaining exploration activities in the Niger Delta
[en] In this paper, a novel kriging-based algorithm for global optimization of computationally expensive black-box functions is presented. This algorithm utilizes a multi-start approach to find all of the local optimal values of the surrogate model and performs searches within the neighboring area around these local optimal positions. Compared with traditional surrogate-based global optimization method, this algorithm provides another kind of balance between exploitation and exploration on kriging-based model. In addition, a new search strategy is proposed and coupled into this optimization process. The local search strategy employs a kind of improved 'Minimizing the predictor' method, which dynamically adjusts search direction and radius until finds the optimal value. Furthermore, the global search strategy utilizes the advantage of kriging-based model in predicting unexplored regions to guarantee the reliability of the algorithm. Finally, experiments on 13 test functions with six algorithms are set up and the results show that the proposed algorithm is very promising.
[en] A practical method for statistically analyzing historic production data from horizontal wells was demonstrated. To date, more than 3,500 horizontal wells have been drilled in Western Canada with an estimated 900 more to be drilled in each of the next few years. The Statistical Technique to Analyze Production History (STAPH) is a new tool with which the petroleum industry can formulate strategy from a production or development engineering point of view. The technique was used to derive a set of production profiles with associated probabilities for producing horizontal wells grouped by lithology, or by lithology and geographic location. The production profile curves can be applied directly to production forecasting and budgeting for recently completed horizontal producers. 8 refs., 13 figs