The uncertain availability of the spectral resource imposes unique challenges in cognitive radio networks. One of the critical issues is to counteract the performance degradation experienced by cognitive users (CUs) due to the activity of primary users (PUs). Since the activity of PUs varies both in frequency and space domain, diversity techniques can represent an efficient way to address this ...

Community structure has been widely identified as a feature of many real-world networks. It has been shown that the antigenic diversity of a pathogen population can be significantly affected by the contact network of its hosts; however, the effects of community structure have not yet been explored. Here, we examine the congruence between patterns of antigenic diversity in pathogen populations i...

Bacterial abundance, biomass, cell volume, and morphological diversity were studied in sediment samples collected from the coastal area of the eastern mid Adriatic Sea. Samples from the topmost 10 cm of sediment were taken monthly from January to December 2002. The number of bacteria varied from 3.54 x 109 cells g–1 in July to 8.08 x 109 cells g–1 in September. Biomass was lowest in May (78 μg ...

Evolutionary genetics studies the patterns and mechanisms of genetic changes underlying evolutionary change. Because biological diversity at all levels (including population, species, and ecosystem diversity) has a genetic basis and is a result of evolution, evolutionary genetics provides insight into the ultimate mechanisms creating biodiversity. Evolutionary genetics utilizes empirical tools ...