On The Strong-Coupling Spectrum of Pure SU(3) Seiberg-Witten Theory

We consider the two complex dimensional moduli space of supersymmetric vacua for low energy effective N=2 SYM with gauge group SU(3). We describe, at the topological level, a consistent model of how the relevant curves of marginal stability (CMS) intertwine with the branch cuts to partition the moduli space into pieces carrying different BPS spectra. At strong coupling we find connected cores which carry a smaller BPS spectrum than that at weak coupling. At the strongest coupling we find double cores which carry a finite BPS spectrum. These include not only states one can deduce from the monodromy group, but three states, bounded away from weak coupling, each of which we interpret as a bound state of two BPS gauge bosons. We find new BPS states at weak coupling corresponding to a excitations of a state with magnetic charge a simple co-root, with respect to the other simple root direction.Comment: 27 pages, uses JHEP.cls; typos corrected, references adde

Neighborhood Dynamics and Price Effects of Superfund Site Clean-Up

This report uses census data to analyze the price effects of superfund site clean-up, inclusive of both direct price effects and indirect effects through clean-up's effect on neighborhood demographic transitions and reinvestment in the housing stock. FRC Report 11

Adaptive Multicast of Multi-Layered Video: Rate-Based and Credit-Based Approaches

Network architectures that can efficiently transport high quality, multicast video are rapidly becoming a basic requirement of emerging multimedia applications. The main problem complicating multicast video transport is variation in network bandwidth constraints. An attractive solution to this problem is to use an adaptive, multi-layered video encoding mechanism. In this paper, we consider two such mechanisms for the support of video multicast; one is a rate-based mechanism that relies on explicit rate congestion feedback from the network, and the other is a credit-based mechanism that relies on hop-by-hop congestion feedback. The responsiveness, bandwidth utilization, scalability and fairness of the two mechanisms are evaluated through simulations. Results suggest that while the two mechanisms exhibit performance trade-offs, both are capable of providing a high quality video service in the presence of varying bandwidth constraints.Comment: 11 page

Capital flows and Japanese asset volatility

Characterizing asset price volatility is an important goal for financial economists. The literature has shown that variables that proxy for the information arrival process can help explain and/or forecast volatility. Unfortunately, however, obtaining good measures of volume and/or order flow is expensive or difficult in decentralized markets such as foreign exchange. We investigate the extent that Japanese capital flows—which are released weekly—reflect information arrival that improves foreign exchange and equity volatility forecasts. We find that capital flows can help explain transitory shocks to GARCH volatility. Transactions by Japanese residents in foreign bond markets have the most explanatory power among capital flows and that power is much greater in the second subsample.Capital movements ; Foreign exchange ; Japan

Inclusive Public Housing: Services for the Hard to House

Evaluates the Chicago Family Case Management Demonstration, a model for comprehensive services targeting families with multiple complex problems that are ineligible for mixed-income housing or unable to negotiate the private market. Outlines implications

A Search for Hydroxylamine (NH_2OH) toward Select Astronomical Sources

Observations of 14 rotational transitions of hydroxylamine (NH_2OH) using the NRAO 12 m telescope on Kitt Peak are reported toward IRC+10216, Orion KL, Orion S, Sgr B2(N), Sgr B2(OH), W3IRS5, and W51M. Although recent models suggest the presence of NH_2OH in high abundance, these observations resulted in non-detection. Upper limits are calculated to be as much as six orders of magnitude lower than those predicted by models. Possible explanations for the lower-than-expected abundance are explored

Vibration suppression and slewing control of a flexible structure

Examined here are the effects of motor dynamics and secondary piezoceramic actuators on vibration suppression during the slewing of flexible structures. The approach focuses on the interaction between the structure, the actuators, and the choice of control law. The results presented here are all simulated, but are based on experimentally determined parameters for the motor, structure, piezoceramic actuators, and piezofilm sensors. The simulation results clearly illustrate that the choice of motor inertia relative to beam inertia makes a critical difference in the performance of the system. In addition, the use of secondary piezoelectric actuators reduces the load requirements on the motor and also reduces the overshoot of the tip deflection. The structures considered here are a beam and a frame. The majority of results are based on a Euler Bernoulli beam model. The slewing frame introduces substantial torsional modes and a more realistic model. The slewing frame results are incomplete and represent work in progress

Static and dynamic characteristics of a piezoceramic strut

The experimental study of a piezoceramic active truss is presented. This active strut is unique in that the piezoceramic configurations allow the stroke length of the strut not to be dependent on the piezoceramic material's expansion range but on the deflection range of the piezoceramic bender segment. A finite element model of a piezoceramic strut segment was constructed. Piezoceramic actuation was simulated using thermally induced strains. This model yielded information on the stiffness and force range of a bender element. The static and dynamic properties of the strut were identified experimentally. Feedback control was used to vary the stiffness of the strut. The experimentally verified model was used to explore implementation possibilities of the strut