软腐欧文氏菌对大白菜根毛吸附的专化性

分3个层次测定了软腐欧文氏菌(Erwinia carotovora susp carotovora)对大白菜根毛吸附的专化性.病菌吸附表现出对寄主根毛表面的选择性、病原细菌与寄主问的专化性、吸附菌量在病菌不同菌株和奇主不同品种间的差异.讨论了病菌吸附专化性在寄主-病原物识别中的意义.     

Power and dependence perspectives on outsourcing decisions

Since the 1980s outsourcing has been a major topic in both economic and management literature. Economic literature tends to focus on the transaction cost perspective. In management literature the core competence approach prevails. An emerging alternative view on outsourcing is the power and dependence perspective. Aspects of power and dependence become visible in four case studies involving the maintenance of capital assets. In each instance both the buyer and supplier sides of the dyad are examined. The paper concludes with managerial implications and research opportunities.     

资产专用性对确权后农地流转的影响

农地确权后,农户对农地转出多持中立或否定的态度,这与产权明晰促进交易的产权理论大相径庭。文章探讨了资产专用性对确权后农地流转的作用机理,并运用吉林省9市1444个农户数据对其进行实证分析。结果表明：农地确权后,土地资产、农业资产、地理位置以及人力资本等专用性抑制农户转出农地,农业资产和人力资本专用性抑制农户提高农地租金,而社会资本专用性则分别存在促进作用;农业资产、地理位置以及人力资本等专用性抑制农户更长时间转出农地;农业资产专用性对转出农地须要签订合约具有抑制作用,而地理位置专用性则存在促进作用。     

论认知隐喻观的理论阐释力

人类对隐喻的研究经历了一个漫长的历史阶段,隐喻理论的解释范围不断扩大。从古希腊的修辞观到对语言本体进行解释的语法隐喻以及语法化研究,从语言和思维相结合的概念隐喻到完全彻底的认知隐喻观,所有这些都对隐喻的研究做出了重大贡献。但一直以来在这些研究的背后,缺乏一种具有统一解释力的理论,即共性。从认知的角度出发我们可以发现,认知域之间的叠加和互动是各类隐喻最基本的工作原理,是隐喻的基本思维方式,是隐喻的共性;另一方面,隐喻的内容又是因民族和文化的不同而有所差异,这是隐喻的个性。     

跨通路实验模式的视觉失匹配负波研究

采用视听觉的跨通路刺激实验模式,通过对ERP实验数据的分析发现:在非注意条件下,顶叶和颞叶的负电位波形不规则,且一致性差;而额叶及枕叶(接近视觉初级投射区)均出现了较明显的视觉早期偏差相关负成分,其潜伏期范围在140～170ms之间,存在通道特异性,与听觉MMN类似。据此得出:视觉早期偏差相关负成分应该是由视觉通路痕迹产生的视觉MMN;视觉早期偏差相关负成分的源有两个,一个位于额叶,另一个位于初级视皮层所在的枕叶处。     

海域物权的特定性探析

海域的特定性和独立性在内涵上是一致的,合称为海域的特定性,其首要问题是如何确定海域的界限。可从横纵两个角度界定：横向包括内水和领海,其中平均大潮高潮线以下的滩涂属于海域;纵向包括水面、水体、海床和底土,其中水面包括水面及其上方自然延伸的空间,纵向界定通过海域分层确权解决。     

浅论女性诗歌中的意象特征

意象是人们感觉到并融入了情感和理智的个别事物及其形状与特征。在当代的女性诗歌作品中,"意象"的种类以及使用方法有很多种,也体现出了意义的暗示性、组合的自由性、表达的特定性等几个特点。通过对女诗人具体诗作中意象的分析可感受到意象的使用丰富了女性诗歌的内涵,也使得女性诗歌的表达更趋多样性。     

Risk of Error and the Kappa Coefficient of a Binary Diagnostic Test in the Presence of Partial Verification

The accuracy of a binary diagnostic test is usually measured in terms of its sensitivity and its specificity, or through positive and negative predictive values. Another way to describe the validity of a binary diagnostic test is the risk of error and the kappa coefficient of the risk of error. The risk of error is the average loss that is caused when incorrectly classifying a non-diseased or a diseased patient, and the kappa coefficient of the risk of error is a measure of the agreement between the diagnostic test and the gold standard. In the presence of partial verification of the disease, the disease status of some patients is unknown, and therefore the evaluation of a diagnostic test cannot be carried out through the traditional method. In this paper, we have deduced the maximum likelihood estimators and variances of the risk of error and of the kappa coefficient of the risk of error in the presence of partial verification of the disease. Simulation experiments have been carried out to study the effect of the verification probabilities on the coverage of the confidence interval of the kappa coefficient.     

资产专用性、索要高价和科层组织

企业为什么存在?什么决定着企业的边界?这两个问题是组织经济学探讨的中心问题.威廉姆森将企业和市场看作是组织交易的不同形式,认为二者的选择是由交易费用决定的,目的在于节约交易费用.通过分析企业内交易和市场交易中交易费用的性质和来源,威廉姆森提出的基本假说是,随着市场交易中关系专用性投资创造的准租金水平的上升和合约不完全程度的上升,合并的可能性将增大.通过考察交易费用理论的基本假设和概念框架发现,该理论为分析企业的纵向一体化程度提供了一种新的有力的工具,但是,该理论对市场交易中潜在的机会主义行为如何在企业内得到克服的分析却是含糊不清的.此外,由于把企业惟一地看作是治理中间产品市场交易障碍的机制,该理论对企业内部组织的解释意义是有限的.     

Sample Size and Power Calculation in Comparing Diagnostic Accuracy of Biomarkers with Pooled Assessments

When testing of a biomarker is costly, pooling of samples becomes a useful and efficient alternative (Faraggi et al., 2003). In this paper, we develop procedures for sample size and power calculations for planning a study comparing the accuracy of biomarkers in diagnosis of diseases with pooled samples. Explicit formulas are derived for several important pooling strategies. The effects of pooling samples on sample size and power of the test are also discussed.