Diversification techniques for web search have recently been developed that assume that, for each query, there is a set of underlying aspects or subtopics that address specific user intents. These techniques attempt to balance the relevance of the retrieved documents with the coverage of the aspects. Evaluation of diversification techniques requires some way of defining a set of aspects for eac...

© Oxford University Press 2015. Published 2015 by Oxford University Press. Molecular phylogenies and ecological associations for approximately two hundred closely related plant species and their specialized, obligate pollinators are depicted without taxonomic names so that we might focus our attention instead on general problems of interpretation. A glance at this web in the tree of life sugges...

Examples of convergent evolution suggest that natural selection can often produce predictable evolutionary outcomes. However, unique histories among species can lead to divergent evolution regardless of their shared selective pressures-and some contend that such historical contingencies produce the dominant features of evolution. A classic example of convergent evolution is the set of Anolis li...

Evolutionary correlations between functionally related character suites are expected as a consequence of coadaptation due to physiological relationships between traits. However, significant correlations may also exist between putatively unrelated characters due to shared relationships between those traits and underlying variables, such as body size. Although such patterns are often dismissed as...

The optimization of large portfolios displays an inherent instability due to estimation error. This poses a fundamental problem, because solutions that are not stable under sample fluctuations may look optimal for a given sample, but are, in effect, very far from optimal with respect to the average risk. In this paper, we approach the problem from the point of view of statistical learning theor...

Understanding of processes driving bacterial speciation requires examination of closely related, recently diversified lineages. To gain an insight into diversification of bacteria, we conducted comparative genomic analysis of two lineages of bioluminescent symbionts, Photobacterium leiognathi and 'P. mandapamensis'. The two lineages are evolutionary and ecologically closely related. Based on th...

The early stages of intraspecific diversity are important for the evolution of diversification and speciation. Early stages of diversification can be seen in individual specialization, where individuals consume only a portion of the diet of the population as a whole, and how such specialization is related to phenotypic diversity within populations. Here, we study the strength of the relationshi...

The role of geography and ecology in speciation are often discussed in the context of phylogenetic niche conservatism (PNC), the propensity of lineages to retain ancestral niche related traits. However, a recent paradigm shift focuses instead on measuring divergence of these traits in conjunction with patterns of speciation. Under this framework, we analyzed the diversification of North America...

This paper contributes to the knowledge about how educational investments are allocated across siblings within the household. More specifically I focus on investigating whether there are signs of diversification, formal schooling being a risky investment. The data used is unusual in that it includes the head of household’s risk preferences in addition to school-related and other information. Th...

Introduction Measures of farm diversification Data and model specification Econometric results Discussion Summary and conclusions Acknowledgements References Appendix Abstract. Farm planning often focuses on optimal diversification with respect to risk, where the riskmanagement strategies combine production, marketing, financial and environmental aspects of the farmfirm. In this study an empiri...