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711.
Jan P. S. Fiselier 《Journal of Quantitative Criminology》1992,8(1):133-151
This paper tests the hypothesis of the stability of punishment as developed by Blumstein and his associates against Dutch prison data. After summarizing the existing empirical evidence, Dutch prison data are presented pertaining to the average daily population in penal institutions, on the one hand, and the number of admissions in these institutions, on the other hand. In three ways it is tested whether these data do support the hypothesis: regression analysis, Box-Jenkins analysis, and the analysis of a few dynamic models as presented by Berket al. (1981). The paper ends with discussing Blumstein's hypothesis and considers the way research into the extent of the prison population should be continued. 相似文献
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713.
A new convention of ‘self-help housing’ has become established over the past 20 years. However, a close examination of the literature shows that this approach is not widely implemented, but remains largely at the level of showcase projects; moreover the lowest income groups are usually not the principal beneficiaries of sites-and-service schemes. The literature gives evidence of powerful political, administrative and economic interests against the large-scale legal delivery of sites-and-services, and in favour of the continued dependence of the poor on illegal access. 相似文献
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715.
Cecil E. Martin William E. Hefley David J. Bristow David Jan Steele 《Policy Sciences》1992,25(1):57-75
This paper addresses certain shortcomings of traditional acquisition approaches, especially for large-scale, unprecedented systems. Shortcomings in the requirements engineering processes are emphasized. We review incremental acquisition approaches and identify issues essential to successful application of incremental acquisition approaches to overcome these shortcomings.In identifying these issues, cases based on systems being developed by the Air Force Space Command are examined. They are the Granite Sentry (GS), Space Defense Operations Centers (SPADOC), and Mobile Command and Control System (MCCS) programs. Three key aspects of the lessons learned from these efforts parallel the steps suggested by a recent Air Force Studies Board report for reducing risk in developing unprecedented systems. These are team-based development, managing requirements uncertainty and change, and increased use of incremental acquisition approaches.This work was sponsored by the U.S. Department of Defense. Approved for public release, distribution unlimited. The views expressed in this article are those of the authors and do not reflect the official policy or position of the U.S. Air Force, the Department of Defense or the U.S. Government. 相似文献
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718.
Anise oil as para-methoxyamphetamine (PMA) precursor 总被引:1,自引:0,他引:1
These days, MDMA is one of the most popular drugs of abuse. Due to its illegality, MDMA and its chemical precursors are watched by governmental organizations in many countries. To avoid conflicts with legal instances, underground chemists have tried to market several new unregulated amphetamine analogues, such as 4-MTA. Para-methoxyamphetamine (PMA), on the other hand, is regulated by law but its precursors are easily obtained since they are cheap and unwatched. This article presents such a case, namely the large scale synthesis of PMA using anethole, a main constituent of anise oil, as precursor. Anethole has been converted to its phenyl acetone analogue via peracid oxidation, while PMA itself has been synthesized using this ketone as precursor in the Leuckart synthesis. The synthesis of PMA using anethole as starting product has been investigated applying GC/MS and GC-HSPME/MS techniques, hereby discovering new specific (4-methoxyphenol) and already identified synthesis impurities (4-methyl-5-(4-methoxyphenyl)pyrimidine, N-(beta-4-methoxyphenylisopropyl)-4-methoxybenzyl methyl ketimine, 1-(4-methoxyphenyl)-N-(2-(4-methoxyphenyl)-1-methylethyl-2-propanamine, 1-(4-methoxyphenyl)-N-methyl-N-(2-(4-methoxyphenyl)-1-methylethyl-2-propanamine, N-(beta-4-methoxyphenylisopropyl)-4-methoxybenzaldimine). The new impurity 4-methoxyphenol is specific for the application of a peracid oxidation method where anethole is used as precursor. 相似文献
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720.
杨建光 《陕西行政学院学报》2003,17(2)
中国已经加入世界贸易组织。要减少加入WTO对农业所产生的冲击,必须实现跨越式发展。而以信息化技术为先 导的农业商新技术将为这次跨越武发展提供机遇。因此,要抓住这一有利时机,加快农业信息化步伐,全面推动现代农业信息技 术在整个农业领域的渗透和应用,促进农业实现“两个根本性转交”,促进农业现代化的早日实现。 相似文献