The unequivocal documentation fintrogression can be a difficult task because alternative hypotheses, uch as convergence or joint retention of the ancestral condition, are difficult todisprove. Similarly, the direction of introgression between two species can often be inferred, but more rarely proven. Molecular markers offer perhaps the best means of demonstrating introgression, because they are...

Concentrations and profiles of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs) were investigated in sediment and plants collected from a salt marsh in the Tejo estuary, Portugal. The highest PCDD/F and dl-PCB concentrations were detected in uncolonized sediments, averaging 325.25 ± 57.55 pg g(-1) ...

Phylogenetic analysis of large datasets using complex nucleotide substitution models under a maximum likelihood framework can be computationally infeasible, especially when attempting to infer confidence values by way of nonparametric bootstrapping. Recent developments in phylogenetics suggest the computational burden can be reduced by using Bayesian methods of phylogenetic inference. However, ...

Habitat degradation can have significant effects on native species inhabiting natural ecosystems. Within oak barrens and oak–pine ecosystems, there is a complex interspecies interaction between the federally endangered Karner blue butterfly ( Lycaeides melissa samuelis) its obligate host plant, wild lupine Lupinus perennis L.). Recruitment of critical for maintaining populations; however, this ...

The interior transmission problem (ITP), which plays a fundamental role in inverse scattering theories involving penetrable defects, is investigated within the framework of mechanical waves scattered by piecewise-homogeneous, elastic or viscoelastic obstacles in a likewise heterogeneous background solid. For generality, the obstacle is allowed to be multiply connected, having both penetrable co...