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71.
目的探讨纤维蛋白胶(FG)粘合法联合神经生长因子(NGF)治疗周围神经损伤的临床疗效。方法选取我院2006年8月至2013年10月就诊的124例腓总神经损伤患者,随机均分为两组,对照组患者单纯使用缝合法,试验组患者在缝合法的基础上配合使用FG粘合法联合NGF治疗,随访6个月以上,分析两组患者的运动功能和患肢感觉疗效。结果试验组患者总有效率明显优于对照组,差异有统计学异议(P<0.05)。结论周围神经损伤的修复与再生过程中使用FG粘合法联合NGF治疗,可有效改善患者症状,安全性高,不良反应较少。  相似文献   
72.
通过对上海近30年的气候因子汇总分析,结合对上 海世博公园主要绿化树种生长状况调查和年度生物量计算,通 过典型相关性分析发现,极端高低温、强风和暴雨等5个气候 因子对树木的生长产生了不同程度的影响,有些因子严重阻碍 了树木的正常生长,成为障碍因子。经过10年的绿化实践验 证,上海世博公园对骨干树种的选择,以乡土树种为主,群落 结构较为稳定,且气候障碍因子对乡土树种的影响较小。在引 种外来树种时,采用气候相似植物区系法,结合植物耐寒、耐 热带图,把种源地划分为2个气候带和3个植物区系,并确定了 最南引种线,成功引种了红花槭等20种观花色叶乔木树种。  相似文献   
73.
We investigate the role of investors’ net hedging strategy (factor) in predicting stock returns and pricing the cross-section of individual stocks and equity portfolios. We estimate stock exposure to changes in the hedging factor and show that the hedging premium is driven by outperformance of stocks with large positive net hedging betas, which explains their higher average returns. We find the positive hedging premium indicates risk-averse investors demand extra compensation to hold stocks with higher equity risk premiums, and they are themselves willing to pay higher prices for stocks with positive hedging betas.  相似文献   
74.
[目的]从静态分析和动态分析两个方面,阐释长江经济带农业绿色生产效率和农业绿色全要素生产率的时空分异特征以及生产率增长来源,以期为提高长江经济带农业绿色发展质量提供科学决策依据。[方法]文章基于资源环境约束的角度,利用MinDS模型和Global Malmquist Luenberger指数相结合的方法,测算长江经济带农业绿色生产效率和农业绿色全要素生产率,并将农业全要素生产率变化分解为纯技术效率变化(PEC)、纯技术变化(PTC)、规模效率变化(SEEC)和规模技术变化(SETC)4个部分。[结果](1)长江经济带农业绿色生产效率水平较高,且呈不断增长趋势,下游地区的农业绿色生产效率高于中、上游,且中、上游与下游地区的差距不断拉大; (2)长江经济带农业绿色全要素生产率增长较快,以3年为1个周期,呈现波动式上升趋势,其增长主要源于纯技术进步和规模技术提高; (3)长江经济带下游农业绿色全要素生产率增长率最高,上游次之,中游最低,其中,下游农业绿色全要素生产率增长主要源于纯技术进步,中游是纯技术效率改进、纯技术进步和规模技术提高共同作用的结果,上游则源于纯技术效率改进、纯技术进步和规模效率提高。[结论]长江经济带上、中、下游三大区域的农业绿色发展水平和发展能力存在较大差异,需制定差异化政策,以调整农业增长模式,促进农业转型升级,实现高质量发展。  相似文献   
75.
The research aims to investigate business value critical success factors (CSFs) of enterprise systems (ES) through their life cycle in pursuit of resilient smart factory for emerging aircraft industry. This article provides an extensive literature analysis of past 22 years based on conscientious criteria of authors: (i) who have published strategic content relevant to CSFs, (ii) received more than 300 citations and (iii) concurrently published two or more papers relevant to ES CSFs. The most cited strategic CSFs were termed as classical CSFs. The 22 CSFs were identified, validated and synthesised for better understanding of success across life cycle by aircraft industry experts. The top 10 empirically verified CSFs have numerous differences with past generic classical CSFs. This article canvases real insights of two distinct views: process and variance approaches of the ES CSFs. The process approach, which is a neglected research area, facilitates the researchers for identification of ES life cycle process coupled with a view of resource deployment when it is needed the most. While the variance approach facilitates practitioners and researchers in finding out which resource (CSF) is relatively more important. The significant findings for ES life cycle can help the practitioners and researchers to make rational decisions throughout the ES life cycle.  相似文献   
76.
This paper aims at decteting what drove the adoption of austerity policies over the period 2010–16 in a panel of 28 European countries. Austerity is identified by year increases in the ratio between the structural primary balance and potential GDP. By means of principal component factor analysis we select the aggregate factors that might affect austerity, namely (i) fiscal consolidation (correction of high deficits and debts), (ii) market discipline (high sovereign spreads, low ratings), (iii) rule-based fiscal discipline (compliance with the Eurozone rules), and macroeconomic stabilisation (consideration for the cyclical position of the economy). Then we estimate a dynamic panel model with the system-GMM method. Results show that the most important contributions to austerity are provided by the market discipline and fiscal consolidation factors together with Excessive Deficit Procedures, with no significant role played by concomitant macroeconomic conditions. Overall, governments complied with orthodox fiscal principles and rules.  相似文献   
77.
We consider the competition among quantity setting players in a linear evolutionary environment. To set their outputs, players adopt, alternatively, the best response rule having perfect foresight or an imitative rule. Players are allowed to change their behavior through an evolutionary mechanism according to which the rule with better performance will attract more followers. The relevant stationary state of the model describes a scenario where players produce at the Cournot‐Nash level. Due to the presence of imitative behavior, we find that the number of players and implementation costs, needed to the best response exploitation, have an ambiguous role in determining the stability properties of the equilibrium and double stability thresholds can be observed. Differently, the role of the intensity of choice, representing the evolutionary propensity to switch to the most profitable rule, has a destabilizing role, in line with the common occurrence in evolutionary models. The global analysis of the model reveals that increasing values of the intensity of choice parameter determine increasing dynamic complexities for the internal attractor representing a population where both decision mechanisms coexist.  相似文献   
78.
In this paper, we study the pricing problems of the European quanto options in which the underlying foreign asset is in imperfectly liquid markets. First, we assume that the dynamics of the underlying foreign asset price are affected by market liquidity and propose a liquidity-adjusted quanto model. This allows for the effects of market liquidity on European quanto option pricing. And then we derive the analytical pricing formulas for four different types of European quanto options. Finally, we empirically investigate the pricing performance of our proposed model with a European quanto construction involving the SSE 50 ETF, as the underlying asset, and the CNY/HKD exchange rate. Empirical results demonstrate that the pricing accuracy of the proposed model is markedly superior to that of the Black-Scholes quanto model. In other words, allowing for liquidity risk in the framework of European quanto option pricing can make markedly improvements in fitting the real market data. Particularly, the improvement rate is high for medium-term and out-of-the-money options. Moreover, these results are robust for different liquidity measures.  相似文献   
79.
80.
在消费者有限理性行为上考虑其策略型和短视型的不同特征,在非理性行为上考虑支付意愿、风险偏好及参考价格三个衡量维度,综合构建消费者效用函数,研究了在消费者行为异质作用下,易逝品零售商的动态定价,并运模拟算例对上述研究进行了演算。研究表明:消费者风险偏好程度较高时,零售商收益会随着策略消费者比例和消费者估值折扣系数的增大而减小,风险偏好较低时可缓解或消除策略消费者的不利影响;零售商的最优定价策略为降价策略;第二阶段消费者产品获得率会对零售商收益产生影响。  相似文献   
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