Search result diversification is one of the key techniques to cope with the ambiguous and/or underspecified information needs of the web users. In the last few years, strategies that are based on the explicit knowledge of query aspects emerged as highly effective ways of diversifying the search results. Our contributions in this work are two-fold. First, we extensively evaluate the performance ...

BACKGROUND AND AIMS Organismal evolution tends to be closely associated with ecological conditions. However, the extent to which this association constrains adaptation or diversification into new habitats remains unclear. We studied habitat evolution in the hyper-diverse angiosperm clade Saxifragales. METHODS We used species-level phylogenies for approx. 950 species to analyse the evolution o...

Corporate diversification is widely believed to be inefficient. It runs against one of the oldest ideas in economics, that specialization is productive. A popular explanation for its prevalence is that firms are plagued with agency problems that allow managers to enter new businesses (from which they privately benefit) at the expense of shareholders. However, the empirical evidence suggests tha...

By using the data of Chinese manufacturing enterprises between 1999 and 2009, the specialization and diversification of China’s exports are calculated. The relationship between financial development and the specialization of export and diversification of exports were studied by using dynamic panel data. It is found that financial credit development could significantly improve specialization of ...

Tropical biotas provide excellent settings in which to explore mechanisms of evolutionary diversification, yet these processes remain poorly understood. Pioneering work on biodiversity patterns and diversification processes in other tropical regions has recently been complemented by studies in Madagascar. Here we review diversity models and diversification mechanisms proposed for the fauna of t...

While the proliferation of the species-rich teleost fish has been ascribed to an ancient genome duplication event at the base of this group, the broader impact of polyploidy on fish evolution and diversification remains poorly understood. Here, we investigate the association between polyploidy and diversification in several fish lineages: the sturgeons (Acipenseridae: Acipenseriformes), the bot...

Life is full of risk. To deal with this uncertainty, many organisms have evolved bet-hedging strategies that spread risk through phenotypic diversification. These rates of diversification can vary by orders of magnitude in different species. Here we examine how key characteristics of risk and organismal ecology affect the fitness consequences of variation in diversification rate. We find that r...

The evolutionary origins of Madagascar's biodiversity remain mysterious despite the fact that relative to land area, there is no other place with consistently high levels of species richness and endemism across a range of taxonomic levels. Most efforts to explain diversification on the island have focused on geographical models of speciation, but recent studies have begun to address the island'...

Time-calibrated molecular phylogenies can help us to understand the origins of the diverse and unique Andean avifauna. Previous studies have shown that the tempo of diversification differed between the Andes and adjacent lowland regions of South America. Andean taxa were found to have speciated more recently and to have avoided the decelerated diversification that is typical of Neotropical lowl...

Bacterial diversification is often observed, but underlying mechanisms are difficult to disentangle and remain generally unknown. Moreover, controlled diversification experiments in ecologically relevant environments are lacking. We studied bacterial diversification in the mammalian gut, one of the most complex bacterial environments, where usually hundreds of species and thousands of bacterial...