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101.
As the 1990-91 Gulf crisis has emphasized, the risk of new oil shocks remains high in the medium to long run. Although energy intensity has decreased in the major countries since the first two oil shocks, the simulation performed with the MIMOSA world model, which is described in this paper, shows that a permanent rise in oil prices still induces direct strong negative consequences in the OECD: a temporary recession, a durable loss in production and employment and a lasting rise in inflation. Moreover, according to the model and due to national dissimilarities, an oil shock in Europe has some asymmetrical effects which are pointed out here. Further simulations test two different economic policy responses in the OECD: a ‘beggar-thy-neighbor’ policy in which each country tries to ‘export’ its unemployment by curbing domestic inflation and wage growth; and a co-ordinated policy supporting both supply and demand. The first leads to a general deflationist overshooting. The second ensures stabilization with a much lower cost in employment.  相似文献   
102.
Bacterial suicide through stress   总被引:9,自引:0,他引:9  
Outside of the laboratory, bacterial cells are constantly exposed to stressful conditions, and an ability to resist those stresses is essential to their survival. However, the degree of stress required to bring about cell death varies with growth phase, amongst other parameters. Exponential phase cells are significantly more sensitive to stress than stationary phase ones, and a novel hypothesis has recently been advanced to explain this difference in sensitivity, the suicide response. Essentially, the suicide response predicts that rapidly growing and respiring bacterial cells will suffer growth arrest when subjected to relatively mild stresses, but their metabolism will continue: a burst of free-radical production results from this uncoupling of growth from metabolism, and it is this free-radical burst that is lethal to the cells, rather than the stress per se. The suicide response hypothesis unifies a variety of previously unrelated empirical observations, for instance induction of superoxide dismutase by heat shock, alkyl-hydroperoxide reductase by osmotic shock and catalase by ethanol shock. The suicide response also has major implications for current [food] processing methods. Received 29 March 1999; received after revision 14 May 1999; accepted 17 May 1999  相似文献   
103.
Two male mouse pheromones, 3,4-dehydro-exo-brevicomin (DHB) and 2-sec-butyldihydrothiazole (SBT), are chiral molecules which were previously tested in their respective bioasays as racemic mixtures. The focus of this study has been to determine the absolute configuration of their natural forms and its relation to stereospecific biological action. DHB was established as the R,R-enantiomer possessing biological activity. Due to an extremely easy racemization of SBT under very mild conditions, enantioselectivity of its transmission and its action at the receptor site appear to be of secondary importance.  相似文献   
104.
This article stresses how little is known about the quality, particularly the relative quality, of macroeconometric models. Most economists make a strict distinction between the quality of a model per se and the accuracy of solutions based on that model. While this distinction is valid, it leaves unanswered how to compare the‘validity’of conditional models. The standard test, the accuracy of ex post simulations, is not definitive when models with differing degrees of exogeneity are compared. In addition, it is extremely difficult to estimate the relative quantitative importance of conceptual problems of models, such as parameter instability across‘policy regimes’ In light of the difficulty in comparisons of conditional macroeconometric models, many model-builders and users assume that the best models are those that have been used to make the most accurate forecasts are those made with the best models. Forecasting experience indicates that forecasters using macroeconometric models have produced more accurate macroeconomic forecasts than either naive or sophisticated unconditional statistical models. It also suggests that judgementally adjusted forecasts have been more accurate than model-based forecasts generated mechanically. The influence of econometrically-based forecasts is now so pervasive that it is difficult to find examples of‘purely judgemental’forecasts.  相似文献   
105.
“三个代表”对统战工作有巨大的指导作用。在“三个代表”的表述中,蕴涵着对统战工作的对象、对统战工作的方针和对统战干部的要求等各方面的逻辑内涵和理论意义。  相似文献   
106.
分析了煤矿建立事故预警机制及应急预案的必要性,探讨了重大事故应急预案的核心要素,展望了煤矿应用预警机制和应急预案的前景。  相似文献   
107.
从中国传统的儒家文化和老子的文化入手进行分析,阐述了他们各自的观点和不同以及两者相结合所产生的巨大的能量,从这里引申到当今的中国的一些基本的国策和他们内在的涵义,从中希望解读中国今后二三十年的国家的运程和走势.  相似文献   
108.
应用有限元方法,采用A,V-As-ψ位函数计算并结合三维场数值计算中的子结构-波阵法,给出了一种能在微机上对远场涡流的三维缺损响应的进行仿真的方法,同时重点研究了相同体积的周向和轴向缺损响应信号及管中涡流分布。研究结果表明,轴向缺损引起的涡流畸变小于周向缺损时的变化,故周向缺损响应信号大于轴向缺损的响应信号。  相似文献   
109.
针对海上低渗油藏注气方案设计受平台环境、油藏特征和工艺条件等众多因素影响而复杂烦琐的问题,将响
应面方法引入水气交替驱方案的设计中。在确定了少量但具有代表性的气驱方案的基础上,通过对其结果的统计分
析,形成了采收率指标与注气时机、水气比、周期注入段塞3 个因素之间的预测模型与响应曲面,并在此基础上开展了
注气参数优化设计。通过该方法可以对研究范围内的气驱方案进行高效地设计、预测和优化,简洁、直观地确定最佳
气驱方案,科学、高效地实现设计目标,提高了海上低渗油藏气驱设计工作的效率和质量。  相似文献   
110.
在对本世纪初美、日、德、英、法发达国家主要的人才战略规划和计划进行梳理的基础上,分析其在科技人才政策方面的新思路和新措施,为促进我国科技人才队伍的建设提供参考。  相似文献   
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