越冬鱼塘溶解氧浓度与罗非鱼的成活率的线性回归分析

通过对罗非鱼越冬鱼塘鱼的成活率及溶解氧浓度的连续监测,运用线性回归分析方法对溶解氧浓度和罗非鱼成活率间关系进行分析,根据结果提出建议和对策。     

PhD students’ work conditions and study environment in university- and industry-based PhD programmes

During the last 10 years, new models of funding and training PhD students have been established in Denmark in order to integrate industry into the entire PhD education. Several programmes have been conducted where it is possible to co-finance PhD scholarships or to become an employee as an industrial PhD in a company. An important question is what impact these new conditions will have on the PhD students’ training, work conditions and study environment. In this article, the new type of programmes will be presented together with data analysis of PhD students’ work conditions and study environment in various programmes mainly based on a research project from 2006. The results of this study show no significant difference between PhD students in a traditional university PhD programme and PhD students in an industrial programme concerning working environment. However, the study shows significant differences in the intercultural dimension, where foreign PhD students are significantly more satisfied with their study environment compared with Danish PhD students. In general the workload is very high and the environment is stressful for all PhD students.     

过去定向者认知加工特点的实验研究

时间定向是个人行为和思想所偏好的方向,主要指向过去的客体和事件。本实验以148名大学生为被试,采用2（高过去定向组,低过去定向组）×2（自我参照,他人参照）×2（消极的过去信息,积极的过去信息）混合设计考察了过去定向者认知加工的特点：结果表明：高过去定向的个体对有关自我的过去信息加工深度深,能产生较好的回忆;并倾向于优先加工与自我有关的消极信息。过去定向者的认知加工具有类似自我图式的性质。对产生该效应的可能原因进行了讨论,并指出今后进一步研究的方向。     

论当代先锋小说的"非小说化"倾向

当代先锋小说在文体形式方面进行了大胆的探索与实验,离传统的小说样式愈来愈远,表现出一种“非小说化”倾向,这主要体现在以下三个方面：在语言方面,当代先锋小说表现出非叙述、非描写的特征,语言由工具变成了本体;在文体方面,先锋小说打破了与诗歌、散文、戏剧等文体之间的明显界限,将不同的文体整合为一个有机的整体,呈现出一种复合文体的趋向;在结构方面,先锋小说采用混合视角进行叙述,打破了传统小说的线性时间结构而趋向三维空间结构。先锋小说的“非小说化”既是先锋小说的创作现状,也是先锋小说发展的未来趋势。     

“鱼鸭共育”生态养殖模型的研究进展

养鱼水域养鸭,不仅可以充分利用水体资源,还可以提高养鸭饵料利用率,提高鱼产量,降低养殖成本,减少精饲料消耗。其基本机理：鸭的游动能够增加水中溶氧,促进水体有机物分解,提供有机碎屑为鱼食用;鸭粪又可直接培育水质,形成水体的良性循环,提高养鱼水体的综合经济效益。就鱼鸭共育的国内外研究概况、目前存在的问题以及生态养殖模式的展望作一总结,并提出了鱼鸭混养的改进模式。     

山区池塘培育瓯江倒刺鲃鱼种试验

通过到山塘培育瓯江倒刺鲃鱼种试验,结果表明:1亩鱼塘和3.5亩山塘,经过8个月的鱼苗培育鱼种试验,获利12 290元,每公顷收入为40 967元,投入产出比为1:1.89,经济和生态效益显著。在试验中提出了养殖过程中的有关注意问题,为山塘培育倒刺鲃规模养殖提供了实践和理论的参考。     

氦原子(e,2e)电离反应的三重微分截面

考虑初末态电子间的关联效应,计算和分析了在共面不对称几何条件下,能量为5500eV和1500eV的入射电子碰撞He原子电离的三重微分截面,并将其计算结果与Dupre等人和Avaldi等人的绝对实验数据及其它理论计算结果进行了比较。计算结果表明:考虑初末态电子间的关联效应的理论模型能够定性地描述这样的反应过程。     

Testing Measurement Invariance Across Unobserved Groups: The Role of Covariates in Factor Mixture Modeling

Factor mixture modeling (FMM) has been increasingly used to investigate unobserved population heterogeneity. This study examined the issue of covariate effects with FMM in the context of measurement invariance testing. Specifically, the impact of excluding and misspecifying covariate effects on measurement invariance testing and class enumeration was investigated via Monte Carlo simulations. Data were generated based on FMM models with (1) a zero covariate effect, (2) a covariate effect on the latent class variable, and (3) covariate effects on both the latent class variable and the factor. For each population model, different analysis models that excluded or misspecified covariate effects were fitted. Results highlighted the importance of including proper covariates in measurement invariance testing and evidenced the utility of a model comparison approach in searching for the correct specification of covariate effects and the level of measurement invariance. This approach was demonstrated using an empirical data set. Implications for methodological and applied research are discussed.     

The Immigrant Paradox in the Problem Behaviors of Youth in the United States: A Meta-analysis

This meta-analysis synthesizes the empirical data on problem behaviors among foreign- (G1) and U.S-born (G2+) youth and explores the effects of immigrant status on youth internalizing and externalizing problems. A random effects meta-regression with robust variance estimates summarized effect sizes for internalizing and externalizing problems across 91 studies (N = 179,315, M_age = 13.98). Results indicated that G1 youth reported significantly more internalizing problems (g = .06), and fewer externalizing problems than G2+ youth (g = −.06). Gender and sample type moderated the effects. The findings provide a first-step toward reconciling mixed support for the immigrant paradox by identifying for whom and under what conditions the immigrant experience serves as a risk or protective factor for youth.     

关于密度函数公式的注记

给出了Z=X^2/a^2＋Y^2/b^2,Z=X^2/a^2-Y^2/b^2,Z=√X^2/a^2＋Y^2/b^2,Z=Y/aX^2的密度函数公式.