The Quantum Hall Effect: Unified Scaling Theory and Quasi-particles at the Edge

We address two fundamental issues in the physics of the quantum Hall effect: a unified description of scaling behavior of conductances in the integral and fractional regimes, and a quasi-particle formulation of the chiral Luttinger Liquids that describe the dynamics of edge excitations in the fractional regime.Comment: 11 pages, LateX, 2 figures (not included, available from the authors), to be published in Proceedings of the International Summer School on Strongly Correlated Electron Systems, Lajos Kossuth University, Debrecen, Hungary, Sept 199

Dynamic coordinated control laws in multiple agent models

We present an active control scheme of a kinetic model of swarming. It has been shown previously that the global control scheme for the model, presented in \cite{JK04}, gives rise to spontaneous collective organization of agents into a unified coherent swarm, via a long-range attractive and short-range repulsive potential. We extend these results by presenting control laws whereby a single swarm is broken into independently functioning subswarm clusters. The transition between one coordinated swarm and multiple clustered subswarms is managed simply with a homotopy parameter. Additionally, we present as an alternate formulation, a local control law for the same model, which implements dynamic barrier avoidance behavior, and in which swarm coherence emerges spontaneously.Comment: 20 pages, 6 figure

Experiential avoidance as a mechanism of change across cognitive-behavioral therapy in a sample of participants with heterogeneous anxiety disorders

Despite the substantial evidence that supports the efficacy of cognitive-behavioral therapy for the treatment of anxiety and related disorders, our understanding of mechanisms of change throughout treatment remains limited. The goal of the current study was to examine changes in experiential avoidance across treatment in a sample of participants (N = 179) with heterogeneous anxiety disorders receiving various cognitive-behavioral therapy protocols. Univariate latent growth curve models were conducted to examine change in experiential avoidance across treatment, followed by parallel process latent growth curve models to examine the relationship between change in experiential avoidance and change in anxiety symptoms. Finally, bivariate latent difference score models were conducted to examine the temporal precedence of change in experiential avoidance and change in anxiety. Results indicated that there were significant reductions in experiential avoidance across cognitive-behavioral treatment, and that change in experiential avoidance was significantly associated with change in anxiety. Results from the latent difference score models indicated that change in experiential avoidance preceded and predicted subsequent changes in anxiety, whereas change in anxiety did not precede and predict subsequent changes in experiential avoidance. Taken together, these results provide additional support for reductions in experiential avoidance as a transdiagnostic mechanism in cognitive-behavioral therapy.First author draf

Beyond the Standard Model in Many Directions

These four lectures constitute a gentle introduction to what may lie beyond the standard model of quarks and leptons interacting through $SU(3)_c \otimes SU(2)_L \otimes U(1)_Y$ gauge bosons, prepared for an audience of graduate students in experimental particle physics. In the first lecture, I introduce a novel graphical representation of the particles and interactions, the double simplex, to elicit questions that motivate our interest in physics beyond the standard model, without recourse to equations and formalism. Lecture 2 is devoted to a short review of the current status of the standard model, especially the electroweak theory, which serves as the point of departure for our explorations. The third lecture is concerned with unified theories of the strong, weak, and electromagnetic interactions. In the fourth lecture, I survey some attempts to extend and complete the electroweak theory, emphasizing some of the promise and challenges of supersymmetry. A short concluding section looks forward.Comment: 64 pages, 43 figures, uses cernrep.cls and other included macros. 2003 Latin-American School of High-Energy Physic