We used participant-produced photography to investigate everyday commuting practices in Cambridge, UK. Photovoice served as an observational method for producing ethnographically rich data. A total of 19 participants produced over 500 photos about their journeys to and from work and took part in photo-elicitation interviews. Three themes emerged. First, many images depicted 'well-being' in comm...

At city level, personal monitoring is the best way to assess people's exposure. However, it is usually estimated from a few monitoring stations. Our aim was to determine the exposure to black carbon (BC) and BC dose for 45 schoolchildren with portable microaethalometers and to evaluate the relationship between personal monitoring and fixed stations at schools (indoor and outdoor) and in an urba...

Let G be a finite p-group. We prove that whenever the commuting probability of G is greater than (2p2 + p− 2)/p5, the unramified Brauer group of the field of G-invariant functions is trivial. Equivalently, all relations between commutators in G are consequences of some universal ones. The bound is best possible, and gives a global lower bound of 1/4 for all finite groups. The result is attained...

— We consider Hermitian N ×N random matrices H distributed according to a probability density dμN(H) = e−N Tr V (H)dH with analytic and uniformly convex V . From work by Zinn-Justin, Collins, and Guionnet & Maida it is known that the large-N limit of the scaled logarithm N−1 lnΩ(NK) of the Fourier transform Ω(K) of dμN(H) for K of finite rank, is a linear functional of the Voiculescu R-transfor...

Using the spectral subspaces obtained in [HS], Brown’s results (cf. [Bro]) on the Brown measure of an operator in a type II1 factor (M, τ) are generalized to finite sets of commuting operators in M. It is shown that whenever T1, . . . , Tn ∈ M are mutually commuting operators, there exists one and only one compactly supported Borel probability measure μT1,...,Tn on B(C) such that for all α1, . ...

We study the classical simulatability of commuting quantum circuits with n input qubits and O(log n) output qubits, where a quantum circuit is classically simulatable if its output probability distribution can be sampled up to an exponentially small additive error in classical polynomial time. First, we show that there exists a commuting quantum circuit that is not classically simulatable unles...

We classify two-qubit commuting Hamiltonians in terms of their computational complexity. Suppose one has a two-qubit commuting Hamiltonian H which one can apply to any pair of qubits, starting in a computational basis state. We prove a dichotomy theorem: either this model is efficiently classically simulable or it allows one to sample from probability distributions which cannot be sampled from ...

In this paper we study the existence of commuting regular elements, verifying the notion left (right) commuting regular elements and its properties in the groupoid G(n). Also we show that G(n) contains commuting regular subsemigroup and give a necessary and sufficient condition for the groupoid G(n) to be commuting regular.

in this paper we introduce the construction of free profinite products of profinite groups withcommuting subgroups. we study a particular case: the proper free profinite products of profinite groups with commuting subgroups. we prove some conditions for a free profinite product of profinite groups with commuting subgroups to be proper. we derive some consequences. we also compute profinite comp...