网络效应一定会导致技术锁定吗?

在网络产业中,往往存在替代技术之间的激烈竞争。传统的观点认为,由于网络效应的作用,技术之间的结果是一种技术成为了产业的主导标准,而该技术的用户则被锁定于该技术之中,从而无法导致最优的均衡结果。因此,政府有必要对技术竞争进行干预。然而,传统的观点忽略了技术赞助者的作用、用户之间自发的协调以及用户偏好的多样化等因素,这些因素在一定程度上能够解决网络效应导致的技术锁定问题。因此,政府不应该对网络产业中的技术竞争进行过多的干预,而是应该做好知识产权保护、提供更多的市场信息以及保障用户的自主选择权。     

手术在治疗跟骨关节内骨折28例的临床效果

目的探讨手术治疗根骨关节内骨折的临床疗效。方法本选取2009年12月～2011年12月我院收治的跟骨关节内骨折患者28例的临床资料。按其来院顺序,将其随即分为两组,切开复位内固定组(A组)和改良式复合外固定支架固定组(B组),每组患者均为14例。比较两组的临床疗效。结果 A组治疗在SandersⅡ型上,其优良率好于B组,且差异具有统计学意义(x2=8.45,P<0.05)。两组在SandersⅢ型-Ⅳ型的治疗上,B组好于A组,差异具有显著统计学意义(x2=14.36,P<0.01)。结论切开复位内固定和改良式复合外固定支架固定治疗根骨关节内骨折临床疗效均较好,且操作简单,并发症少,值得在临床中广泛应用。     

基于减缓热岛效应的公园绿地布局 优化研究

城市化进程加快导致城市热岛效应问题日益突出, 公园绿地在降温方面具有重要作用,如何通过公园绿地布局以 减缓热岛效应是当前值得思考的问题。以福州市主城区为研究 区,利用辐射传输方程和泰森多边形分析城市热岛情况及公园 绿地布局现状,采用P-中值模型结合城市用地规划确定公园 绿地布局优化方案,结果表明：1)福州市主城区的整体温度偏 高,其热岛范围达城市总面积的11.78%;2)共提取福州市主 城区公园绿地47个,总面积为11.11km2,占主城区总面积 的4.47%,公园绿地布局总体不能满足人们的需要;3)利用 P-中值模型对公园绿地供需情况进行分析,得出18个公园绿 地需要优化,其中包括福州动物园、环南公园等12个一级优化 公园绿地,以及屏山公园、琴亭湖公园等6个二级优化公园绿 地;4)结合福州市中心城区用地规划,得到50个潜在公园绿 地建设点,主要集中于城门镇、盖山镇及新店镇。     

From real estate to consumption: the role of credit markets in the USA

The aim of this article is to test whether the credit market conditions affect the strength of transmission of real estate wealth effects on household consumption in the US economy. Although many different works have dealt with the analysis of the existence of a real estate wealth effect, most of them as a reaction to the dramatic increase of housing prices in several OECD countries, there are only few papers analysing whether the consumption response depends on the positive or negative sign of the wealth shock and, as far as we know, none of them takes the effects of credit market conditions on that asymmetric response into account. This article tries to fill the existing gap in the literature on this matter. From an econometric perspective, we estimate the asymmetries in the consumption response within the momentum threshold autoregressive model (M-TAR) proposed by Enders and Siklos (2001), but following Stevans (2004), it is applied to a multivariate framework. The main results show that the credit market conditions play a significant role in the transmission of changes in real estate wealth to consumption. In addition, we find that there exists an asymmetric behaviour in the US aggregate consumption spending responses to real estate wealth and credit market shocks, which is only significant when a negative shock takes place.     

宫颈癌新辅助化疗的临床疗效

目的探讨宫颈癌术前应用新辅助化疗的临床疗效。方法 68例宫颈癌术前采用2个疗程的新辅助化疗后进行手术,观察近期疗效。结果 68例患者化疗2个疗程后的临床总有效率为70.1%。经过术前辅助化疗后,进行广泛性子宫切除加盆腔淋巴结清扫手术,全部患者均顺利切除病灶。结论术前新辅助化疗对宫颈癌Ⅰb1~Ⅱb期患者治疗安全有效,可缩小肿瘤体积,提高手术切除率及疗效,进一步改善患者的生活质量。     

中美制造业双边贸易对美国相对工资差距的影响研究*

在新古典贸易理论一般均衡的框架之下,运用1997-2014年中美两国的投入产出、贸易和工资数据,本文定量考察了中美制造业产品的双边贸易同美国制造业相对工资差距的关系。结果发现,美国从中国的净进口对美国制造业非熟练劳动力和熟练劳动力相对工资差距扩大存在影响,但影响幅度较小,贸易并不是引起相对收入差距扩大的唯一原因。但随着中美双边制造业贸易的进一步发展,美中贸易对美国工资差距的影响可能越来越大,以保护非熟练劳动力为名对中国产品实施贸易限制的呼声将会更高。     

供给侧改革中资源与能源行业去产能政策效果研究

中国经济历经复苏和快速增长阶段后,部分产业出现产能过剩现象,产业结构的不均衡变化导致了GDP增速放缓。2016年初中国政府提出供给侧结构性改革,旨在通过“三去一降一补”政策调整产业结构,刺激经济发展。本文构建了一个包含资源与能源产业的一般均衡模型,量化分析中国供给侧结构性改革的政策效果。研究表明,在去产能政策削减上游资源产业的产出后,政策冲击会传导至下游能源产业,导致化石能源相对于绿色能源产量下降14.04%,能源结构实现优化。随后的政策对比实验引入了新能源补贴、碳排放税征收及资源税收缴等财政手段,与去产能政策进行效果对比。实验结果显示,3种政策在不同程度上实现了能源结构调整,其中征收碳税的政策使化石能源占比降幅最大,但同时会使资本利率上升,加重企业融资成本;新能源补贴与资源税的政策也可以实现调控目标,但与去产能政策相比效果更弱。     

REGIME DEPENDENT EFFECT OF OUTPUT GROWTH ON OUTPUT GROWTH UNCERTAINTY: EVIDENCE FROM OECD COUNTRIES

This paper studies the impact of output growth on output growth uncertainty by considering two important issues hitherto not properly and adequately addressed to in the existing empirical studies specifying this relationship. These are: (i) the possible existence of a threshold level of output growth, and the consequent identification of two regimes characterized by high and low output growth, and (ii) whether or not the coefficient capturing the causal link is different in these two output growth states. This paper proposes a regime switching model to study this asymmetric effect for 16 OECD countries. Based on monthly time‐series observations, our results strongly support that the impact varies significantly between the two output growth regimes with the coefficient in the high growth regime being negative for majority of the countries.     

Wagner’s law versus displacement effect

The public sector has grown dramatically over the past few centuries in many developed countries. In this article, we use wavelet methods to distinguish between two leading explanations for this growth – Wagner’s law and the displacement effect. In doing so, we use the long-term data of 10 OECD countries for a maximum time span of 1800–2009. We find that the validity of Wagner’s law is likely to vary strongly over time for each country. A roughly similar feature in most of the countries is that the law is less valid in the earliest stage of economic development as well as in the advanced stages, with the validity tending to follow an inverted U-shaped pattern with economic development. Further, our results indicate that the long-run growth of government size cannot be adequately explained by Wagner’s law. On the other hand, the displacement effect appears to account for the bulk of the growth in most of the countries.     

Wealth effect and investor sentiment

This paper investigated the relationship between the U.S. stock and housing markets as well as their influence on the wealth effect of consumption and found that the stock market sentiment index can explain changes in the wealth effect. The empirical results indicate that these two markets exert a wealth effect on consumption. The estimation results of the Markov-switching model indicate two states: a state in which the stock market influences its coexistence with the housing market and a state in which the housing and stock markets are unrelated. Public optimism regarding stock market investments affects the probability of transitioning between these states.