Negative density dependence may cause reduced clustering among individuals of the same species, and evidence is accumulating that conspecific density-dependent self-thinning is an important mechanism regulating the spatial structure of plant populations. This study evaluates that specific density dependence in three very large observational studies representing three successional stages in a te...

There is increasing recognition that high self-esteem is heterogeneous. Recent research suggests that individuals who report having high self-esteem (i.e., have high explicit self-esteem) behave more defensively to the extent that they have relatively low implicit self-esteem. The current studies test whether individuals with high explicit self-esteem are more likely to discriminate ethnically,...

Semantic heterogeneity is a common problem when trying to unify information from disparate data systems. In order to overcome these heterogeneities it is generally understood that no one system or convention is the best, rather that mechanisms need to be implemented in which researchers can both agree on terms or keywords used and also the establishment of a keyword structure so their relations...

Predicting the effect of climate change on biodiversity is a multifactorial problem that is complicated by potentially interactive effects with habitat properties and altered species interactions. In a microcosm experiment with communities of microalgae, we analysed whether the effect of rising temperature on diversity depended on the initial or the final temperature of the habitat, on the rate...

BACKGROUND The knowledge of scientific dishonesty is scarce and heterogeneous. Therefore this study investigates the experiences with and the attitudes towards various forms of scientific dishonesty among PhD-students at the medical faculties of all Norwegian universities. METHOD Anonymous questionnaire distributed to all post graduate students attending introductory PhD-courses at all medica...

We show that production rules and persistent queues together provide a convenient mechanism for maintaining consistency in semantically heterogeneous multidatabase environments. We describe a speci cation language and methods for automatically deriving production rules that maintain (1) existence dependencies, in which the presence of data in one database implies the presence of related data in...

In order to use distributed and heterogeneous scientific databases effectively, semantic heterogeneities have to be detected and resolved. To solve this problem, we propose architecture for managing metadata and metadata schema using a metadata registry. A metadata registry is a place to keep facts about characteristics of data that are necessary for data sharing and exchange in a specific doma...

Population heterogeneity is ubiquitous in social science. The very objective of social science research is not to discover abstract and universal laws but to understand population heterogeneity. Due to population heterogeneity, causal inference with observational data in social science is impossible without strong assumptions. Researchers have long been concerned with two potential sources of b...

This paper uses longitudinal data from China to examine the causal relationship between structural social capital and health among Chinese older adults. We employ various econometric strategies to control for the potential endogeneity of social capital and account for the possible contextual confounding effects by including community-level social capital. We use three indicators to measure indi...

Today, many pregnant women take a brief period of time off from work to give birth. In this paper, I identify the effects of pregnancy employment on health at birth. My initial results show that pregnancy employment has beneficial effects. However, these effects often become statistically insignificant when I control for earnings from pregnancy employment, when I exclusively examine women emplo...