Two nationwide studies examine endoscopist performance and colorectal cancer after colonoscopy. Surveillance screening colonoscopy is based on characteristics of removed adenomas but not the endoscopists. In this issue Gastroenterology, Wieszczy et al examined endoscopists (CRC) risk in a Polish cohort. A total 173,288 colonoscopies were performed between 2000 2011 followed up until 2017. Of 26...

Covering models have found many applications in a wide variety of real-world problems; nevertheless, some assumptions of covering models are not realistic enough. Accordingly, a general approach would not be able to answer the needs of encountering varied aspects of real-world considerations. Assumptions like the unavailability of servers, uncertainty, and evaluating more factors at the same ti...

In this note we continue the study of asymptotic invariants of Riemannian tori (e.g. see [BuI] and references there). By asymptotic invariants we mean invariants which do not change under passing to finite covers. In [BuI] we show that the asymptotic volume growth of a Riemannian torus is at least as fast as that of a flat one. One may ask what are the possible values of “asymptotic isoperimetr...

A graph group, or right-angled Artin group, is a group given by a presentation where the only relators are commutators of the generators. A graph group presentation corresponds in a natural way to a simplicial graph, with each generator corresponding to a vertex, and each commutator relator corresponding to an edge. Suppose that G is a graph group whose corresponding graph is a tree and H is a ...

Suppose S is a surface of genus ≥ 2, f : S → S is a surface homeomorphism isotopic to a pseudo-Anosov map α and suppose S̃ is the universal cover of S and F and A are lifts of f and α respectively. A result of A. Fathi shows there is a semiconjugacy Θ : S̃ → L̄ × L̄ from F to Ā, where L̄ (L̄) is the completion of the R-tree of leaves of the stable (resp. unstable) foliation for A and Ā is the map ind...

Let G be the universal cover of the group of automorphisms of a symmetric tube domain and let P = L N be its Shilov boundary parabolic subgroup. This paper attaches an irreducible unitary representation of G to each of the (finitely many) L-orbits on n*. The Hilbert space of the representation consists of functions on the orbit which are square-integrable with respect to a certain L-equivariant...

We consider the following question: given A ∈ SL(2,R), which potentials q for the second order Sturm-Liouville problem have A as its Floquet multiplier? More precisely, define the monodromy map μ taking a potential q ∈ L2([0, 2π]) to μ(q) = Φ̃(2π), the lift to the universal cover G = ̃ SL(2,R) of SL(2,R) of the fundamental matrix map Φ : [0, 2π] → SL(2,R), Φ(0) = I, Φ(t) = (