Dipsadidae is the most diversified family of snakes, composed of species showing an impressive variety of color patterns. Some species are cryptic whereas others have contrasting patterns comprised by bright colors alternated with darker shades, including particular combinations of vivid colors characteristic of coral snakes (Elapidae). Species with such patterns are thought to be mimics of cor...

Drosophila melanogaster is widely used as a model in DNA variation studies. Patterns of polymorphism have, however, been affected by the history of this species, which is thought to have recently spread out of Africa to the rest of the world. We analyzed DNA sequence variation in 11 populations, including four continental African and seven non-African samples (including Madagascar), at four ind...

Let C(T) denote the poset of subtrees of a tree T with respect to the inclusion ordering. Jacobson, Kézdy and Seif gave a single example of a tree T for which C(T) is not Sperner, answering a question posed by Penrice. The authors then ask whether there exist an infinite family of trees T such that C(T) is not Sperner. This paper provides such a family.

1. Predators often prey on individuals that are sick or otherwise weakened. Although previous studies have shown higher abundance of parasites in prey, whether prey have elevated loads of micro-organisms remains to be determined. 2. We quantified the abundance of bacteria and fungi on feathers of woodpigeons Columba palumbus L., jays Garrulus glandarius L. and blackbirds Turdus merula L. that e...

We prove that there exist natural generalizations of the classical bootstrap percolation model on Z that have non-trivial critical probabilities, and moreover we characterize all homogeneous, local, monotone models with this property. Van Enter [28] (in the case d = r = 2) and Schonmann [25] (for all d > r > 2) proved that r-neighbour bootstrap percolation models have trivial critical probabili...

Globally coherent patterns of phase can be obscured by analysis techniques that aggregate brain activity measures across-trials, whether prior to source localization or for estimating inter-areal coherence. We analyzed, at single-trial level, whole head MEG recorded during an observer-triggered apparent motion task. Episodes of globally coherent activity occurred in the delta, theta, alpha and ...

If φ is a nontrivial automorphism of a thick building ∆ of purely infinite type, we prove that there is no bound on the distance that φ moves a chamber. This has the following group-theoretic consequence: If G is a group of automorphisms of ∆ with bounded quotient, then the center of G is trivial.

OBJECTIVE Chronic pain is a well-known morbidity associated with neurofibromatosis (NF) for which better therapies are needed. Surgery, radiation, and pain medications have been utilized, but often fail to relieve debilitating pain. One patient at our institution was noted to have near complete resolution of pain after treatment with bevacizumab for progressive neurologic deficit associated wit...