Cognitive radio (CR) is seen as one of the enabling technologies for realizing a new regulatory spectrum management paradigm, viz. opportunistic spectrum sharing (OSS). In the OSS paradigm, unlicensed users (a.k.a. secondary users) opportunistically operate in fallow licensed spectrum on a non-interference basis to licensed users (a.k.a. incumbent or primary users). Incumbent users have absolut...

Although there is a large body of theory on spatial competitive coexistence, very little of it involves comparative analyses of alternative mechanisms. We thus have limited knowledge of the conditions under which multiple spatial mechanisms can operate or of emergent properties arising from interactions between mechanisms. Here we present a mathematical framework that allows for comparative ana...

This letter introduced a new R package ‘coexist’ which can perform species coexistence simulation and analysis. The package was initially developed for understanding the role of different combinations of varying species growth rates, dispersal ability, habitat heterogeneity, and competition interaction on influencing species coexistence under fluctuating environment. Further versions could intr...

Species diversity in nature is accomplished by coexistence. In a spatial environment, inferior but rapidly moving species can coexist with superior but relatively stationary species. Recent work showed that chaotic dynamics can provide the spatiotemporal variation in the fitness required for coexistence, via the dynamical mechanism of synchronization and intermittency. Utilizing a realistic mod...

Coexistence of many competitive species is very common in natural plant communities. For example, almost all forests and grasslands consist of various species. Extremely high biodiversity is seen in tropical rain forests. Grassland communities also often consist of many species. In plant communities, spatially competitive species of plants coexist in a mosaic pattern. Communities with a single ...

The rise of antimicrobial resistance in many pathogens presents a major challenge to the treatment and control of infectious diseases. Furthermore, the observation that drug-resistant strains have risen to substantial prevalence but have not replaced drug-susceptible strains despite continuing (and even growing) selective pressure by antimicrobial use presents an important problem for those who...

Background and Importance: The coexistence of pituitary adenoma and another type of brain tumor is a very rare clinical scenario. Even though such a presentation can be an incidental event but the possible pathogenesis of coexistence of different lesions in the sella and suprasellar region has not yet been elucidated. Case Presentation: Two cases of concomitant sellar and suprasellar region ...

0[ Intraspeci_c aggregation at a single spatial scale can promote the coexistence of competitors[ This paper demonstrates how this same mechanism can be applied to the many systems that are patchy at two scales\ with patches nested within {superpatches|[ 1[ Data are presented from a _eld study showing that insects living in rotting fruits have aggregated distributions in the fruits under a sing...

A fundamental result in the evolutionary-game paradigm of cyclic competition in spatially extended ecological systems, as represented by the classic Reichenbach-Mobilia-Frey (RMF) model, is that high mobility tends to hamper or even exclude species coexistence. This result was obtained under the hypothesis that individuals move randomly without taking into account the suitability of their local...