各省区科技资源配置增长平稳度分析

科技资源配置是科技管理和科技政策关心的核心问题,而配置规模是其中最主要的问题。根据科技资源发展平稳性的影响因素,设计发展平稳度指数,运用SPSS软件和SAS软件,采用主成分分析法,研究配置规模发展的平稳性,探讨影响整体发展平稳性的主要因素。研究发现,科技活动人员发展平稳性水平对资源配置规模平稳性的影响最大。中国各省区不同类型资源发展的平稳性水平不同,且越是均衡发展,就越有利于提升科技资源的整体配置效率。     

Rating Migrations: The Effect of History and Time

We examine the effect of rating history and the passage of time on the rating migration hazard for corporate debt issuers. Controlling for industry effects and the evolution of business and political cycles, the results consistently show that the next change of rating depends more strongly on rating history than it does on the current rating. However, there are significant interactions between the main effects of rating history and the duration of the current rating. The result is substantial decay in the effects of rating history the longer a rating remains unchanged. This decay effect is stronger for downgrades and for ratings in the speculative category.     

The 4% strategy revisited: a pre-commitment mean-variance optimal approach to wealth management

In contrast to single-period mean-variance (MV) portfolio allocation, multi-period MV optimal portfolio allocation can be modified slightly to be effectively a down-side risk measure. With this in mind, we consider multi-period MV optimal portfolio allocation in the presence of periodic withdrawals. The investment portfolio can be allocated between a risk-free investment and a risky asset, the price of which is assumed to follow a jump diffusion process. We consider two wealth management applications: optimal de-accumulation rates for a defined contribution pension plan and sustainable withdrawal rates for an endowment. Several numerical illustrations are provided, with some interesting implications. In the pension de-accumulation context, Bengen (1994)’s [J. Financial Planning, 1994, 7, 171–180], historical analysis indicated that a retiree could safely withdraw 4% of her initial retirement savings annually (in real terms), provided that her portfolio maintained an even balance between diversified equities and U.S. Treasury bonds. Our analysis does support 4% as a sustainable withdrawal rate in the pension de-accumulation context (and a somewhat lower rate for an endowment), but only if the investor follows an MV optimal portfolio allocation, not a fixed proportion strategy. Compared with a constant proportion strategy, the MV optimal policy achieves the same expected wealth at the end of the investment horizon, while significantly reducing the standard deviation of wealth and the probability of shortfall. We also explore the effects of suppressing jumps so as to have a pure diffusion process, but assuming a correspondingly larger volatility for the latter process. Surprisingly, it turns out that the MV optimal strategy is more effective when there are large downward jumps compared to having a high volatility diffusion process. Finally, tests based on historical data demonstrate that the MV optimal policy is quite robust to uncertainty about parameter estimates.     

表面活性剂对牙齿的溶蚀作用

人体牙齿中含有大量的钙离子,而表面活性剂具有溶蚀钙离子的作用.笔者通过EDTA滴定法,在模拟人体口腔温度的条件下,利用不同的表面活性剂溶液浸泡牙齿,研究不同的表面活性剂对牙齿中钙离子的溶蚀程度.从而评价表面活性剂对人体牙齿的长期影响.     

大学生网络游戏成瘾矫治的个案研究

通过一例网络游戏成瘾大学生矫治的研究,探讨这类学生的心理健康教育的方法。研究结果表明:针对个案对象的表现特征,探究产生网络成瘾的原因,并采取适宜地矫治方法,能够使网络游戏成瘾大学生的心理和行为得到改善。     

阿尔金地区牛鼻子梁铜镍矿特征及其发现意义

阿尔金成矿带南缘的牛鼻子梁地区首次发现硫化物铜镍矿床,矿体赋存于加里东晚期超基性岩脉底部接触带。初步分析矿床成因为熔离贯入改造型,并有后期热液叠加。铜镍矿(化)主要与基性-超基性杂岩体有关。目前牛鼻子梁地区已发现Cu-Ni矿化超基性杂岩体5处。以牛鼻子梁铜镍矿的发现为依据,加强阿尔金和柴达木周缘地区找矿工作投入和成矿条件、成矿规律的研究,对阿尔金山和柴达木周缘地区广布的基性-超基性岩体群中寻找硫化物铜镍矿有深远意义。     

工程监理中投资控制存在问题浅析

本文从工程监理的角度出发,分析了业主、监理工程师、施工企业单位对投资控制的影响。提出解决影响投资控制的四个环节的问题,以达到合理控制工程造价的目的。     

管理信息系统精品课程建设的思考与探索

对管理信息系统精品课程建设过程存在的问题进行了探讨,并从课程教学体系设计、教学手段改革、教学方法研究、教学队伍培养、教材建设规划和实验教学几个方面进行了深入的探索与创新。     

市场风险资本监管框架演进过程分析

本文梳理了巴塞尔委员会关于市场风险监管框架的演进历史,将其分为三个阶段:将市场风险纳入监管框架、关注特定风险及处理新增风险和证券化产品.市场风险监管框架演进呈现三个特点:风险头寸划分更细,风险认识更清晰,风险管理技术逐渐提高.随着市场环境变化、技术和实践的发展,市场风险监管将更臻成熟.     

论应对污染转移中付费措施的合理采用

传统的环境管制性手段存在诸多漏洞,且容易因管理者的自利而呈现软化,不足以应对复杂的污染转移形势。要从源头上预防污染转移,就应让污染者承担污染防治和控制措施的合理成本,消除污染转移的可能经济利益。环境保护的经济手段会避免传统的命令加控制管理方法的一些弊病,能使污染者付费落到实处。因而,面对愈演愈烈的污染转移,我国应妥善采用环境税、生态补偿等环保经济措施,并采取一些手段抑制其可能带来的不公平影响。