常压下单质的熔化熵

应用分子动力学方法计算了常压下Al、Cu、Ni、Ta、W、Si六种单质的熔化温度（Tm）、熔化焓（△Hm）和熔化熵（△Sm）,并验证了Richard定律、梅平等人总结的经验公式和Kubachewski提出的经验公式在常压下的适用性.计算结果表明：这三种定律（经验公式）对Al、Cu、Ni、Ta、W单质符合得较好,对Si单质存在较大误差.     

电气化铁路轨道电路干扰信号检测新方法

提出了一种基于耦合绝缘子的新型检测方法。为了提高测量精度,采用参数估计的算法用来校准新型测量装置的传输函数;并通过对信号处理单元的校准来补偿相位差。实验表明：该测量方法可以精确地测量高频率干扰信号。     

基于字典学习的医学图像融合

稀疏表示能够有效地表示图像的固有特征,利用KSVD学习算法对30幅自然图像训练得到了鲁棒的字典,利用“滑窗”策略对两幅源图像进行分块,使用OMP算法在字典上对各图像块进行稀疏分解,分解后的系数采用系数绝对值选大法进行融合,进而得到融合后和图像块.理论分析与实验结果表明,该方法能够有效地对已配准的待融合图像进行融合,融合后的结果无论是视觉效果还是客观评价参数均优于文中对比方法的效果.     

Precursors to probation and parole agent intent to send informational,emotional, and esteem social support messages to female clients

Supervising agents serve as sources of social support for over one million women in the US on probation and parole who strive to avoid recidivism. Little is known about the supportive messages agents intend to provide their female clients or their precursors. The optimal matching model of social support is used in an investigation of the precursors to agents’ intent to send different types of social support messages to the women they supervise. Results indicated that supervising agents intended to provide informational support in the form of suggestions or advice, esteem support in the form of compliments, and emotional support in the form of encouragement to the women. Both agent communication pattern and offender level variables were precursors to the intent to send informational support messages, but only agent communication pattern variables predicted the intent to send emotional support messages.     

功利估算的实践困境

功利主义的后果最大化原则要求对行为的功利后果进行计量、估算和比较,但严格意义上的功利估算在实践中却遭遇了困境,这种困境包括功利后果的可公度性与是否可以累加和相互抵消的问题、各种功利后果的明确的量值问题、具体的计算方法和概率的问题、功利后果的复杂性问题等。以边沁为代表的古典功利主义的探讨和论证没有真正解决这些问题,现代功利主义将行为或制度的客观效果而非主体的感性体验作为功利估算的对象,为功利主义走出困境提供了启示。功利估算走出困境的可能性在于一方面要扩大评价的信息基础,另一方面要诉诸人的理性能力和人的道德直觉、价值偏好等非理性能力所构成的综合评价标准。     

Software review

Amos 3.51. Written by James L. Arbuckle. Distributed by SmallWaters Corporation, 1507 East 53rd Street, Suite 452, Chicago, IL 60615. Regular price, $465, educational price, $325, possible upgrade discounts.     

Evaluating Model Fit With Ordered Categorical Data Within a Measurement Invariance Framework: A Comparison of Estimators

A paucity of research has compared estimation methods within a measurement invariance (MI) framework and determined if research conclusions using normal-theory maximum likelihood (ML) generalizes to the robust ML (MLR) and weighted least squares means and variance adjusted (WLSMV) estimators. Using ordered categorical data, this simulation study aimed to address these queries by investigating 342 conditions. When testing for metric and scalar invariance, Δχ² results revealed that Type I error rates varied across estimators (ML, MLR, and WLSMV) with symmetric and asymmetric data. The Δχ² power varied substantially based on the estimator selected, type of noninvariant indicator, number of noninvariant indicators, and sample size. Although some the changes in approximate fit indexes (ΔAFI) are relatively sample size independent, researchers who use the ΔAFI with WLSMV should use caution, as these statistics do not perform well with misspecified models. As a supplemental analysis, our results evaluate and suggest cutoff values based on previous research.     

Evaluation of Test Statistics for Robust Structural Equation Modeling With Nonnormal Missing Data

A 2-stage robust procedure as well as an R package, rsem, were recently developed for structural equation modeling with nonnormal missing data by Yuan and Zhang (2012). Several test statistics that have been used for complete data analysis are employed to evaluate model fit in the 2-stage robust method. However, properties of these statistics under robust procedures for incomplete nonnormal data analysis have never been studied. This study aims to systematically evaluate and compare 5 test statistics, including a test statistic derived from normal-distribution-based maximum likelihood, a rescaled chi-square statistic, an adjusted chi-square statistic, a corrected residual-based asymptotical distribution-free chi-square statistic, and a residual-based F statistic. These statistics are evaluated under a linear growth curve model by varying 8 factors: population distribution, missing data mechanism, missing data rate, sample size, number of measurement occasions, covariance between the latent intercept and slope, variance of measurement errors, and downweighting rate of the 2-stage robust method. The performance of the test statistics varies and the one derived from the 2-stage normal-distribution-based maximum likelihood performs much worse than the other four. Application of the 2-stage robust method and of the test statistics is illustrated through growth curve analysis of mathematical ability development, using data on the Peabody Individual Achievement Test mathematics assessment from the National Longitudinal Survey of Youth 1997 Cohort.     

《国家学生体质健康标准》与《学生体质健康标准(试行方案)》比较

通过对3604名大学生进行《学生体质健康标准(试行方案)》与《国家学生体质健康标准》的比较研究,分析了《新标准》在测试项目、权重系数、评分标准和评价等级等方面的实用性和科学性.研究表明,《新标准》在测试项目上仍然存在分类不清,选测项目相关度不高的问题.《新标准》调整了权重系数和评分标准,对大学生提出了更高的要求,可以更好地调动学生锻炼的积极性,达到增强体质的目的.另外,《新标准》中肺活量体重指数、立定跳远的提高幅度较大,学生在短期内无法达到要求,需要做进一步的调整.     

从关联数据的应用场景看信息服务发展的新动向

文章分析关联数据的应用,对比传统信息服务,归纳总结信息服务发展的新动向,即：从资源组织技术来看,出现了从文献资源整合向数据融合与跨界混搭的新发展;从检索技术来看,出现了从分面浏览、高级字段检索向基于对象和关系的语义检索的新发展;从支持第三方和嵌入式服务来看,出现了从开放接口向支持开放数据、开放服务的技术新发展。