土地流转中为什么会形成大量小农复制

土地流转是实现规模化经营的前提之一,然而土地流转中却出现大量小农复制,从而影响土地流转的质量和效果。运用12省(自治区)2 553份农户问卷,详细分析土地流转中小农复制的现状及其形成原因。研究发现：(1)农户流转耕地面积不大,转入户流转面积20亩及以下的约占总转入户数的60.3％,转出户流转面积5亩及以下的约占总转出户数的74.38％,转出户中仍然经营土地的约占总转出户数的74％。(2)农业分工发达使生产更加方便、文化传统形成路径依赖、禀赋效应产生“价值幻觉”以及公共服务不健全使未来存在不确定性导致转出户流转部分土地。乡土社会限制土地流转范围和经营风险增加风险感知导致转入户流转小规模土地。     

From the Digital Divide to the Connectivity Dividend Difference: A Connectivity Capital Perspective*

The access divide was once the basic form of the digital divide. The development of Internet infrastructure has narrowed the access divide and increased application coverage, but it has also touched off a connectivity dividend difference. Taking the online market as an example, we examine the sources of the dividend difference and the factors influencing it with in a connectivity framework. We found that the narrowing of the access divide has resulted in enhanced connectivity and platform development, giving people the chance to benefit from transforming the various assets in which they have previously invested into differentiated compound connectivity capital. In the course, the scale and rate of the conversion are affected by two multiplier effects and especially by online platforms. The process is ultimately expressed in the dividend difference.     

Conditional Akaike Information Criteria for a Class of Poisson Mixture Models with Random Effects

Focusing on the model selection problems in the family of Poisson mixture models (including the Poisson mixture regression model with random effects and zero‐inflated Poisson regression model with random effects), the current paper derives two conditional Akaike information criteria. The criteria are the unbiased estimators of the conditional Akaike information based on the conditional log‐likelihood and the conditional Akaike information based on the joint log‐likelihood, respectively. The derivation is free from the specific parametric assumptions about the conditional mean of the true data‐generating model and applies to different types of estimation methods. Additionally, the derivation is not based on the asymptotic argument. Simulations show that the proposed criteria have promising estimation accuracy. In addition, it is found that the criterion based on the conditional log‐likelihood demonstrates good model selection performance under different scenarios. Two sets of real data are used to illustrate the proposed method.     

公共卫生支出、健康结果与卫生投入政策——基于189个国家和地区的面板门槛分析（1995—2011年）

利用189个国家和地区1995—2011年的数据实证检验公共卫生支出规模对一个国家的健康结果（婴儿死亡率和出生时的平均期望寿命）的影响，结果表明，公共卫生支出占GDP的比重对婴儿死亡率和出生时的平均期望寿命的影响具有门槛效应，门槛值分别位于1.9%和6.62%。分段回归结果显示，公共卫生支出占GDP的比重低于1.9%时，公共卫生投入对出生时的平均期望寿命没有显著影响，对婴儿死亡率的影响较弱；超过1.9%后，公共卫生投入的规模效应开始体现，对健康结果指标的影响均显著增强；超过6.62%后，公共卫生投入对婴儿死亡率的影响不再显著，对出生时平均期望寿命的弹性系数不再变化，单位边际贡献不再增加。中国当前政府卫生投入规模仍然较低，需要继续增大公共资金投入、降低个人卫生支出比重。     

身处异代成相知尽在悠悠故国情——从朱彝尊对周密《绝妙好词》的接受说起

《词综》是浙西词派的理论代表。《词综》和《绝妙好词》在宗派意识和对“雅”词的崇尚方面，表现出极大的相似性。这表明，朱彝尊在编选《词综》时曾自觉接受周密《绝妙好词》的影响。其深层原因在于，浙西词宗朱彝尊和周密有相似的遗民情怀。     

基于协同效应的知识创新团队伙伴选择方法

在知识创新团队的伙伴选择问题中着重考虑了伙伴间的协同效应信息。首先,分析了伙伴之间的协同关系与协同效应,描述了考虑多个协同效应评价指标的知识创新团队伙伴选择问题;然后,建立了团队伙伴选择的数学模型,该模型是一个0-1二次整数规划问题,为了求解该问题,开发了一种GRASP启发式算法;最后,通过一个实例分析说明了所提出方法的可行性和实际应用价值。     

家电下乡政策的消费效应评估——基于全国221个村庄的4年跟踪调查

以全国221个村庄所获得的4年调查数据作为研究基础,对"家电下乡"政策的消费效应予以评估和分析。调查表明,家电下乡政策消费效应的最大特征是农民消费需求的释放,其中包括全国消费总额的上升,户均消费额增幅达到8成,全国各地消费总量和户均消费数量的增加。但家电下乡政策的消费效应在实践中也遇到了持续性疲软的难题,如农民收入的限制作用,农民购买下乡产品比重偏低,政府补贴额和补贴程序不足,政策宣传和解说不到位。为了使家电下乡政策的消费效应持续起效,必须不断完善政策,使家电下乡政策的实惠真正落实到农民身上。     

Locally best invariant test for outliers in a gamma type distribution

It is shown that the locally best invariant test for the existence of outliers for scale parameters of the gamma distribution is given by Bartholomew's test for exponentiality which is the ratio of the sum of squares of the data to the square of the sample mean. The optimality robustness, including null and nonnull robustness of the test is shown. A small simulation study to compare the power among the other eight competitive tests for testing exponentiality is performed. It is seen that the locally best invariant test is not always best but is reasonably good. It is slightly better than Cochran's test and suffers less from the limiting masking effect.