Urban fiscal austerity, infrastructure provision and the struggle for regional transit in 'Motor City'

Studies suggest that urban fiscal crises trigger the institutional separation of strategic services from general purpose municipal functions. Traditional reformists have highlighted the economic benefits of regional approaches. Global austerity has created fiscal problems for central cities and suburbs alike, transforming the motives for regional solutions. This paper examines how the City of Detroit engineered a new regional arrangement with the surrounding suburbs to raise debt for the delivery of mass transit infrastructure. It represents a dual 'spatial fix' in the form of (i) a 'state territorial fix' providing fiscally stressed municipalities access to municipal bond markets and (ii) a 'speculative spatial fix' that benefits the Detroit growth coalition by linking regional mass transit to the prospect of land-use intensification. © The Author 2014

Perturbative 2-body Parent Hamiltonians for Projected Entangled Pair States

We construct parent Hamiltonians involving only local 2-body interactions for a broad class of Projected Entangled Pair States (PEPS). Making use of perturbation gadget techniques, we define a perturbative Hamiltonian acting on the virtual PEPS space with a finite order low energy effective Hamiltonian that is a gapped, frustration-free parent Hamiltonian for an encoded version of a desired PEPS. For topologically ordered PEPS, the ground space of the low energy effective Hamiltonian is shown to be in the same phase as the desired state to all orders of perturbation theory. An encoded parent Hamiltonian for the double semion string net ground state is explicitly constructed as a concrete example.Comment: 26 pages, 4 figures, v2 published versio

Active Queue Management for Fair Resource Allocation in Wireless Networks

This paper investigates the interaction between end-to-end flow control and MAC-layer scheduling on wireless links. We consider a wireless network with multiple users receiving information from a common access point; each user suffers fading, and a scheduler allocates the channel based on channel quality,but subject to fairness and latency considerations. We show that the fairness property of the scheduler is compromised by the transport layer flow control of TCP New Reno. We provide a receiver-side control algorithm, CLAMP, that remedies this situation. CLAMP works at a receiver to control a TCP sender by setting the TCP receiver's advertised window limit, and this allows the scheduler to allocate bandwidth fairly between the users

Toric codes and quantum doubles from two-body Hamiltonians

We present here a procedure to obtain the Hamiltonians of the toric code and Kitaev quantum double models as the low-energy limits of entirely two-body Hamiltonians. Our construction makes use of a new type of perturbation gadget based on error-detecting subsystem codes. The procedure is motivated by a projected entangled pair states (PEPS) description of the target models, and reproduces the target models' behavior using only couplings that are natural in terms of the original Hamiltonians. This allows our construction to capture the symmetries of the target models

Generation, Translocation, and Action of Nitric Oxide in Living Systems

Nitric oxide (NO) is a gaseous diatomic radical that is involved in a wide range of physiological and pathological functions in biology. Conceptually, the biochemistry of NO can be separated into three stages: generation (stage 1), translocation (stage 2), and action (stage 3). In stage 1 the oxygenase domain of NO synthase converts L-arginine to L-citrulline and NO (g). Owing to its short-lived nature, this molecule is converted into a different nitrogen oxide such as NO[subscript 2], an organonitrosyl such as a nitrosothiol, or a metal nitrosyl such as a heme-nitrosyl, for transportation in stage 2. Each of these derivatives features unique physical characteristics, chemical reactivity, and biological activity. Upon delivery in stage 3, NO exerts its physiological or pathological function by reaction with biomolecules containing redox-active metals or other residues.National Science Foundation (U.S.) (Grant CHE-0907905